v3.13.9

fixes #4992

.github/workflows/build.yml

@@ -0,0 +1,58 @@
+name: Build testing
+on:
+  pull_request:
+  push:
+    branches: [ master ]
+jobs:
+  ufuzz:
+    strategy:
+      fail-fast: false
+      matrix:
+        options:
+          - '-mb braces'
+          - '--ie8 -c'
+          - '-mc'
+          - '-p acorn --toplevel -mco spidermonkey'
+          - '--toplevel -mc passes=3,pure_getters,unsafe'
+        script:
+          - acorn.sh
+          - bootstrap.sh
+          - buble.sh
+          - butternut.sh
+          - mathjs.sh
+          - rollup-es.sh
+          - rollup-ts.sh
+          - sucrase.sh
+          - web-tooling-benchmark.sh
+        include:
+          - node: '14'
+            script: acorn.sh
+          - node: '14'
+            script: bootstrap.sh
+          - node: '14'
+            script: buble.sh
+          - node: '14'
+            script: butternut.sh
+          - node: '14'
+            script: mathjs.sh
+          - node: '8'
+            script: rollup-es.sh
+          - node: '14'
+            script: rollup-ts.sh
+          - node: '14'
+            script: sucrase.sh
+          - node: '14'
+            script: web-tooling-benchmark.sh
+    name: ${{ matrix.script }} ${{ matrix.options }}
+    runs-on: ubuntu-latest
+    env:
+      NODE: ${{ matrix.node }}
+      OPTIONS: ${{ matrix.options }}
+      SCRIPT: ${{ matrix.script }}
+    steps:
+      - uses: actions/checkout@v2
+      - name: Perform uglify, build & test
+        shell: bash
+        run: |
+          . ./test/release/install.sh
+          ./test/release/$SCRIPT $OPTIONS

.github/workflows/ci.yml

@@ -7,7 +7,7 @@ jobs:
   test:
     strategy:
       matrix:
-        node: [ '0.8', '0.10', '0.12', '4', '6', '8', '10', '12', latest ]
+        node: [ '0.8', '0.10', '0.12', '4', '6', '8', '10', '12', '14', latest ]
         os: [ ubuntu-latest, windows-latest ]
         script: [ compress, mocha, release/benchmark, release/jetstream ]
         exclude:
@@ -29,20 +29,5 @@ jobs:
       - name: Perform tests
         shell: bash
         run: |
-          git clone --branch v1.6.0 --depth 1 https://github.com/jasongin/nvs.git ~/.nvs
+          . ./test/release/install.sh
-          while ! timeout 60 bash -c '. ~/.nvs/nvs.sh add $NODE && nvs use $NODE'; do
-            cd ~/.nvs
-            while !(git clean -xdf); do echo "'git clean' failed - retrying..."; done
-            cd -
-          done
-          . ~/.nvs/nvs.sh --version
-          nvs use $NODE
-          node --version
-          npm config set audit false
-          npm config set optional false
-          npm config set save false
-          npm config set strict-ssl false
-          npm config set update-notifier false
-          npm --version
-          while !(npm install); do echo "'npm install' failed - retrying..."; done
           node test/$TYPE

.github/workflows/ufuzz.yml

@@ -2,11 +2,14 @@ name: Fuzzing
 on:
   pull_request:
   schedule:
-    - cron: '*/5 * * * *'
+    - cron: '*/15 * * * *'
+  workflow_dispatch:
+  workflow_run:
+    branches: [ master ]
+    types: [ completed ]
+    workflows: [ 'Build testing', CI ]
 env:
   BASE_URL: https://api.github.com/repos/${{ github.repository }}
-  CAUSE: ${{ github.event_name }}
-  RUN_NUM: ${{ github.run_number }}
   TOKEN: ${{ github.token }}
 jobs:
   ufuzz:
@@ -30,35 +33,12 @@ jobs:
       NODE: ${{ matrix.node }}
     steps:
       - uses: actions/checkout@v2
-      - name: Install GNU Core Utilities
-        if: ${{ startsWith(matrix.os, 'macos') }}
-        env:
-          HOMEBREW_NO_BOTTLE_SOURCE_FALLBACK: 1
-          HOMEBREW_NO_INSTALL_CLEANUP: 1
-        shell: bash
-        run: |
-          while !(brew install coreutils); do echo "'brew install' failed - retrying..."; done
       - name: Perform fuzzing
         shell: bash
         run: |
-          git clone --branch v1.6.0 --depth 1 https://github.com/jasongin/nvs.git ~/.nvs
+          . ./test/release/install.sh
-          while ! timeout 60 bash -c '. ~/.nvs/nvs.sh add $NODE && nvs use $NODE'; do
+          if [[ $GITHUB_EVENT_NAME == "pull_request" ]]; then
-            cd ~/.nvs
-            while !(git clean -xdf); do echo "'git clean' failed - retrying..."; done
-            cd -
-          done
-          . ~/.nvs/nvs.sh --version
-          nvs use $NODE
-          node --version
-          npm config set audit false
-          npm config set optional false
-          npm config set save false
-          npm config set strict-ssl false
-          npm config set update-notifier false
-          npm --version
-          while !(npm install); do echo "'npm install' failed - retrying..."; done
-          if [[ $CAUSE == "schedule" ]]; then
-            node test/ufuzz/job $BASE_URL $TOKEN $RUN_NUM
-          else
             node test/ufuzz/job 5000
+          else
+            node test/ufuzz/job $BASE_URL $TOKEN $GITHUB_RUN_NUMBER
           fi

README.md

@@ -92,6 +92,9 @@ a double dash to prevent input files being used as option arguments:
     -o, --output <file>         Output file path (default STDOUT). Specify `ast` or
                                 `spidermonkey` to write UglifyJS or SpiderMonkey AST
                                 as JSON to STDOUT respectively.
+    --annotations               Process and preserve comment annotations.
+                                (`/*@__PURE__*/` or `/*#__PURE__*/`)
+    --no-annotations            Ignore and discard comment annotations.
     --comments [filter]         Preserve copyright comments in the output. By
                                 default this works like Google Closure, keeping
                                 JSDoc-style comments that contain "@license" or
@@ -221,10 +224,10 @@ Example:
 To enable the mangler you need to pass `--mangle` (`-m`).  The following
 (comma-separated) options are supported:
 
-- `eval` (default `false`) -- mangle names visible in scopes where `eval` or
+- `eval` (default: `false`) — mangle names visible in scopes where `eval` or
   `with` are used.
 
-- `reserved` (default: `[]`) -- when mangling is enabled but you want to
+- `reserved` (default: `[]`) — when mangling is enabled but you want to
   prevent certain names from being mangled, you can declare those names with
   `--mangle reserved` — pass a comma-separated list of names.  For example:
 
@@ -491,46 +494,51 @@ if (result.error) throw result.error;
 
 ## Minify options
 
-- `compress` (default `{}`) — pass `false` to skip compressing entirely.
+- `annotations` — pass `false` to ignore all comment annotations and elide them
+  from output. Useful when, for instance, external tools incorrectly applied
+  `/*@__PURE__*/` or `/*#__PURE__*/`. Pass `true` to both compress and retain
+  comment annotations in output to allow for further processing downstream.
+
+- `compress` (default: `{}`) — pass `false` to skip compressing entirely.
   Pass an object to specify custom [compress options](#compress-options).
 
-- `ie8` (default `false`) -- set to `true` to support IE8.
+- `ie8` (default: `false`) — set to `true` to support IE8.
 
-- `keep_fnames` (default: `false`) -- pass `true` to prevent discarding or mangling
+- `keep_fnames` (default: `false`) — pass `true` to prevent discarding or mangling
   of function names.  Useful for code relying on `Function.prototype.name`.
 
-- `mangle` (default `true`) — pass `false` to skip mangling names, or pass
+- `mangle` (default: `true`) — pass `false` to skip mangling names, or pass
   an object to specify [mangle options](#mangle-options) (see below).
 
-  - `mangle.properties` (default `false`) — a subcategory of the mangle option.
+  - `mangle.properties` (default: `false`) — a subcategory of the mangle option.
     Pass an object to specify custom [mangle property options](#mangle-properties-options).
 
-- `nameCache` (default `null`) -- pass an empty object `{}` or a previously
+- `nameCache` (default: `null`) — pass an empty object `{}` or a previously
   used `nameCache` object if you wish to cache mangled variable and
   property names across multiple invocations of `minify()`. Note: this is
   a read/write property. `minify()` will read the name cache state of this
   object and update it during minification so that it may be
   reused or externally persisted by the user.
 
-- `output` (default `null`) — pass an object if you wish to specify
+- `output` (default: `null`) — pass an object if you wish to specify
   additional [output options](#output-options).  The defaults are optimized
   for best compression.
 
-- `parse` (default `{}`) — pass an object if you wish to specify some
+- `parse` (default: `{}`) — pass an object if you wish to specify some
   additional [parse options](#parse-options).
 
-- `sourceMap` (default `false`) -- pass an object if you wish to specify
+- `sourceMap` (default: `false`) — pass an object if you wish to specify
   [source map options](#source-map-options).
 
-- `toplevel` (default `false`) -- set to `true` if you wish to enable top level
+- `toplevel` (default: `false`) — set to `true` if you wish to enable top level
   variable and function name mangling and to drop unused variables and functions.
 
-- `v8` (default `false`) -- enable workarounds for Chrome & Node.js bugs.
+- `v8` (default: `false`) — enable workarounds for Chrome & Node.js bugs.
 
-- `warnings` (default `false`) — pass `true` to return compressor warnings
+- `warnings` (default: `false`) — pass `true` to return compressor warnings
   in `result.warnings`. Use the value `"verbose"` for more detailed warnings.
 
-- `webkit` (default `false`) -- enable workarounds for Safari/WebKit bugs.
+- `webkit` (default: `false`) — enable workarounds for Safari/WebKit bugs.
   PhantomJS users should set this option to `true`.
 
 ## Minify options structure
@@ -615,116 +623,121 @@ to be `false` and all symbol names will be omitted.
 
 ## Parse options
 
-- `bare_returns` (default `false`) -- support top level `return` statements
+- `bare_returns` (default: `false`) — support top level `return` statements
 
-- `html5_comments` (default `true`)
+- `html5_comments` (default: `true`)
 
-- `shebang` (default `true`) -- support `#!command` as the first line
+- `shebang` (default: `true`) — support `#!command` as the first line
 
 ## Compress options
 
-- `arguments` (default: `true`) -- replace `arguments[index]` with function
+- `annotations` (default: `true`) — Pass `false` to disable potentially dropping
+  functions marked as "pure".  A function call is marked as "pure" if a comment
+  annotation `/*@__PURE__*/` or `/*#__PURE__*/` immediately precedes the call. For
+  example: `/*@__PURE__*/foo();`
+
+- `arguments` (default: `true`) — replace `arguments[index]` with function
   parameter name whenever possible.
 
-- `arrows` (default: `true`) -- apply optimizations to arrow functions
+- `arrows` (default: `true`) — apply optimizations to arrow functions
 
-- `assignments` (default: `true`) -- apply optimizations to assignment expressions
+- `assignments` (default: `true`) — apply optimizations to assignment expressions
 
-- `awaits` (default: `true`) -- apply optimizations to `await` expressions
+- `awaits` (default: `true`) — apply optimizations to `await` expressions
 
-- `booleans` (default: `true`) -- various optimizations for boolean context,
+- `booleans` (default: `true`) — various optimizations for boolean context,
   for example `!!a ? b : c → a ? b : c`
 
-- `collapse_vars` (default: `true`) -- Collapse single-use non-constant variables,
+- `collapse_vars` (default: `true`) — Collapse single-use non-constant variables,
   side effects permitting.
 
-- `comparisons` (default: `true`) -- apply certain optimizations to binary nodes,
+- `comparisons` (default: `true`) — apply certain optimizations to binary nodes,
   e.g. `!(a <= b) → a > b`, attempts to negate binary nodes, e.g.
   `a = !b && !c && !d && !e → a=!(b||c||d||e)` etc.
 
-- `conditionals` (default: `true`) -- apply optimizations for `if`-s and conditional
+- `conditionals` (default: `true`) — apply optimizations for `if`-s and conditional
   expressions
 
-- `dead_code` (default: `true`) -- remove unreachable code
+- `dead_code` (default: `true`) — remove unreachable code
 
-- `default_values` (default: `true`) -- drop overshadowed default values
+- `default_values` (default: `true`) — drop overshadowed default values
 
-- `directives` (default: `true`) -- remove redundant or non-standard directives
+- `directives` (default: `true`) — remove redundant or non-standard directives
 
-- `drop_console` (default: `false`) -- Pass `true` to discard calls to
+- `drop_console` (default: `false`) — Pass `true` to discard calls to
   `console.*` functions. If you wish to drop a specific function call
   such as `console.info` and/or retain side effects from function arguments
   after dropping the function call then use `pure_funcs` instead.
 
-- `drop_debugger` (default: `true`) -- remove `debugger;` statements
+- `drop_debugger` (default: `true`) — remove `debugger;` statements
 
-- `evaluate` (default: `true`) -- Evaluate expression for shorter constant
+- `evaluate` (default: `true`) — Evaluate expression for shorter constant
   representation. Pass `"eager"` to always replace function calls whenever
   possible, or a positive integer to specify an upper bound for each individual
   evaluation in number of characters.
 
-- `expression` (default: `false`) -- Pass `true` to preserve completion values
+- `expression` (default: `false`) — Pass `true` to preserve completion values
   from terminal statements without `return`, e.g. in bookmarklets.
 
-- `functions` (default: `true`) -- convert declarations from `var` to `function`
+- `functions` (default: `true`) — convert declarations from `var` to `function`
   whenever possible.
 
-- `global_defs` (default: `{}`) -- see [conditional compilation](#conditional-compilation)
+- `global_defs` (default: `{}`) — see [conditional compilation](#conditional-compilation)
 
-- `hoist_exports` (default: `true`) -- hoist `export` statements to facilitate
+- `hoist_exports` (default: `true`) — hoist `export` statements to facilitate
   various `compress` and `mangle` optimizations.
 
-- `hoist_funs` (default: `false`) -- hoist function declarations
+- `hoist_funs` (default: `false`) — hoist function declarations
 
-- `hoist_props` (default: `true`) -- hoist properties from constant object and
+- `hoist_props` (default: `true`) — hoist properties from constant object and
   array literals into regular variables subject to a set of constraints. For example:
   `var o={p:1, q:2}; f(o.p, o.q);` is converted to `f(1, 2);`. Note: `hoist_props`
   works best with `toplevel` and `mangle` enabled, alongside with `compress` option
   `passes` set to `2` or higher.
 
-- `hoist_vars` (default: `false`) -- hoist `var` declarations (this is `false`
+- `hoist_vars` (default: `false`) — hoist `var` declarations (this is `false`
   by default because it seems to increase the size of the output in general)
 
-- `if_return` (default: `true`) -- optimizations for if/return and if/continue
+- `if_return` (default: `true`) — optimizations for if/return and if/continue
 
-- `imports` (default: `true`) -- drop unreferenced import symbols when used with `unused`
+- `imports` (default: `true`) — drop unreferenced import symbols when used with `unused`
 
-- `inline` (default: `true`) -- inline calls to function with simple/`return` statement:
+- `inline` (default: `true`) — inline calls to function with simple/`return` statement:
-  - `false` -- same as `0`
+  - `false` — same as `0`
-  - `0` -- disabled inlining
+  - `0` — disabled inlining
-  - `1` -- inline simple functions
+  - `1` — inline simple functions
-  - `2` -- inline functions with arguments
+  - `2` — inline functions with arguments
-  - `3` -- inline functions with arguments and variables
+  - `3` — inline functions with arguments and variables
-  - `true` -- same as `3`
+  - `true` — same as `3`
 
-- `join_vars` (default: `true`) -- join consecutive `var` statements
+- `join_vars` (default: `true`) — join consecutive `var` statements
 
-- `keep_fargs` (default: `false`) -- discard unused function arguments except
+- `keep_fargs` (default: `false`) — discard unused function arguments except
   when unsafe to do so, e.g. code which relies on `Function.prototype.length`.
   Pass `true` to always retain function arguments.
 
-- `keep_infinity` (default: `false`) -- Pass `true` to prevent `Infinity` from
+- `keep_infinity` (default: `false`) — Pass `true` to prevent `Infinity` from
   being compressed into `1/0`, which may cause performance issues on Chrome.
 
-- `loops` (default: `true`) -- optimizations for `do`, `while` and `for` loops
+- `loops` (default: `true`) — optimizations for `do`, `while` and `for` loops
   when we can statically determine the condition.
 
-- `merge_vars` (default: `true`) -- combine and reuse variables.
+- `merge_vars` (default: `true`) — combine and reuse variables.
 
-- `negate_iife` (default: `true`) -- negate "Immediately-Called Function Expressions"
+- `negate_iife` (default: `true`) — negate "Immediately-Called Function Expressions"
   where the return value is discarded, to avoid the parens that the
   code generator would insert.
 
-- `objects` (default: `true`) -- compact duplicate keys in object literals.
+- `objects` (default: `true`) — compact duplicate keys in object literals.
 
-- `passes` (default: `1`) -- The maximum number of times to run compress.
+- `passes` (default: `1`) — The maximum number of times to run compress.
   In some cases more than one pass leads to further compressed code.  Keep in
   mind more passes will take more time.
 
-- `properties` (default: `true`) -- rewrite property access using the dot notation, for
+- `properties` (default: `true`) — rewrite property access using the dot notation, for
   example `foo["bar"] → foo.bar`
 
-- `pure_funcs` (default: `null`) -- You can pass an array of names and
+- `pure_funcs` (default: `null`) — You can pass an array of names and
   UglifyJS will assume that those functions do not produce side
   effects.  DANGER: will not check if the name is redefined in scope.
   An example case here, for instance `var q = Math.floor(a/b)`.  If
@@ -736,24 +749,24 @@ to be `false` and all symbol names will be omitted.
   overhead (compression will be slower). Make sure symbols under `pure_funcs`
   are also under `mangle.reserved` to avoid mangling.
 
-- `pure_getters` (default: `"strict"`) -- If you pass `true` for
+- `pure_getters` (default: `"strict"`) — If you pass `true` for
   this, UglifyJS will assume that object property access
   (e.g. `foo.bar` or `foo["bar"]`) doesn't have any side effects.
   Specify `"strict"` to treat `foo.bar` as side-effect-free only when
   `foo` is certain to not throw, i.e. not `null` or `undefined`.
 
-- `reduce_funcs` (default: `true`) -- Allows single-use functions to be
+- `reduce_funcs` (default: `true`) — Allows single-use functions to be
   inlined as function expressions when permissible allowing further
   optimization.  Enabled by default.  Option depends on `reduce_vars`
   being enabled.  Some code runs faster in the Chrome V8 engine if this
   option is disabled.  Does not negatively impact other major browsers.
 
-- `reduce_vars` (default: `true`) -- Improve optimization on variables assigned with and
+- `reduce_vars` (default: `true`) — Improve optimization on variables assigned with and
   used as constant values.
 
-- `rests` (default: `true`) -- apply optimizations to rest parameters
+- `rests` (default: `true`) — apply optimizations to rest parameters
 
-- `sequences` (default: `true`) -- join consecutive simple statements using the
+- `sequences` (default: `true`) — join consecutive simple statements using the
   comma operator.  May be set to a positive integer to specify the maximum number
   of consecutive comma sequences that will be generated. If this option is set to
   `true` then the default `sequences` limit is `200`. Set option to `false` or `0`
@@ -762,70 +775,68 @@ to be `false` and all symbol names will be omitted.
   occasions the default sequences limit leads to very slow compress times in which
   case a value of `20` or less is recommended.
 
-- `side_effects` (default: `true`) -- Pass `false` to disable potentially dropping
+- `side_effects` (default: `true`) — drop extraneous code which does not affect
-  functions marked as "pure".  A function call is marked as "pure" if a comment
+  outcome of runtime execution.
-  annotation `/*@__PURE__*/` or `/*#__PURE__*/` immediately precedes the call. For
-  example: `/*@__PURE__*/foo();`
 
-- `spreads` (default: `true`) -- flatten spread expressions.
+- `spreads` (default: `true`) — flatten spread expressions.
 
-- `strings` (default: `true`) -- compact string concatenations.
+- `strings` (default: `true`) — compact string concatenations.
 
-- `switches` (default: `true`) -- de-duplicate and remove unreachable `switch` branches
+- `switches` (default: `true`) — de-duplicate and remove unreachable `switch` branches
 
-- `templates` (default: `true`) -- compact template literals by embedding expressions
+- `templates` (default: `true`) — compact template literals by embedding expressions
   and/or converting to string literals, e.g. `` `foo ${42}` → "foo 42"``
 
-- `top_retain` (default: `null`) -- prevent specific toplevel functions and
+- `top_retain` (default: `null`) — prevent specific toplevel functions and
   variables from `unused` removal (can be array, comma-separated, RegExp or
   function. Implies `toplevel`)
 
-- `toplevel` (default: `false`) -- drop unreferenced functions (`"funcs"`) and/or
+- `toplevel` (default: `false`) — drop unreferenced functions (`"funcs"`) and/or
   variables (`"vars"`) in the top level scope (`false` by default, `true` to drop
   both unreferenced functions and variables)
 
-- `typeofs` (default: `true`) -- Transforms `typeof foo == "undefined"` into
+- `typeofs` (default: `true`) — Transforms `typeof foo == "undefined"` into
   `foo === void 0`.  Note: recommend to set this value to `false` for IE10 and
   earlier versions due to known issues.
 
-- `unsafe` (default: `false`) -- apply "unsafe" transformations (discussion below)
+- `unsafe` (default: `false`) — apply "unsafe" transformations (discussion below)
 
-- `unsafe_comps` (default: `false`) -- compress expressions like `a <= b` assuming
+- `unsafe_comps` (default: `false`) — compress expressions like `a <= b` assuming
   none of the operands can be (coerced to) `NaN`.
 
-- `unsafe_Function` (default: `false`) -- compress and mangle `Function(args, code)`
+- `unsafe_Function` (default: `false`) — compress and mangle `Function(args, code)`
   when both `args` and `code` are string literals.
 
-- `unsafe_math` (default: `false`) -- optimize numerical expressions like
+- `unsafe_math` (default: `false`) — optimize numerical expressions like
   `2 * x * 3` into `6 * x`, which may give imprecise floating point results.
 
-- `unsafe_proto` (default: `false`) -- optimize expressions like
+- `unsafe_proto` (default: `false`) — optimize expressions like
   `Array.prototype.slice.call(a)` into `[].slice.call(a)`
 
-- `unsafe_regexp` (default: `false`) -- enable substitutions of variables with
+- `unsafe_regexp` (default: `false`) — enable substitutions of variables with
   `RegExp` values the same way as if they are constants.
 
-- `unsafe_undefined` (default: `false`) -- substitute `void 0` if there is a
+- `unsafe_undefined` (default: `false`) — substitute `void 0` if there is a
   variable named `undefined` in scope (variable name will be mangled, typically
   reduced to a single character)
 
-- `unused` (default: `true`) -- drop unreferenced functions and variables (simple
+- `unused` (default: `true`) — drop unreferenced functions and variables (simple
   direct variable assignments do not count as references unless set to `"keep_assign"`)
 
-- `varify` (default: `true`) -- convert block-scoped declaractions into `var`
+- `varify` (default: `true`) — convert block-scoped declaractions into `var`
   whenever safe to do so
 
-- `yields` (default: `true`) -- apply optimizations to `yield` expressions
+- `yields` (default: `true`) — apply optimizations to `yield` expressions
 
 ## Mangle options
 
-- `eval` (default `false`) -- Pass `true` to mangle names visible in scopes
+- `eval` (default: `false`) — Pass `true` to mangle names visible in scopes
   where `eval` or `with` are used.
 
-- `reserved` (default `[]`) -- Pass an array of identifiers that should be
+- `reserved` (default: `[]`) — Pass an array of identifiers that should be
   excluded from mangling. Example: `["foo", "bar"]`.
 
-- `toplevel` (default `false`) -- Pass `true` to mangle names declared in the
+- `toplevel` (default: `false`) — Pass `true` to mangle names declared in the
   top level scope.
 
 Examples:
@@ -852,18 +863,18 @@ UglifyJS.minify(code, { mangle: { toplevel: true } }).code;
 
 ### Mangle properties options
 
-- `builtins` (default: `false`) -- Use `true` to allow the mangling of builtin
+- `builtins` (default: `false`) — Use `true` to allow the mangling of builtin
   DOM properties. Not recommended to override this setting.
 
-- `debug` (default: `false`) -— Mangle names with the original name still present.
+- `debug` (default: `false`) — Mangle names with the original name still present.
   Pass an empty string `""` to enable, or a non-empty string to set the debug suffix.
 
-- `keep_quoted` (default: `false`) -— Only mangle unquoted property names.
+- `keep_quoted` (default: `false`) — Only mangle unquoted property names.
 
-- `regex` (default: `null`) -— Pass a RegExp literal to only mangle property
+- `regex` (default: `null`) — Pass a RegExp literal to only mangle property
   names matching the regular expression.
 
-- `reserved` (default: `[]`) -- Do not mangle property names listed in the
+- `reserved` (default: `[]`) — Do not mangle property names listed in the
   `reserved` array.
 
 ## Output options
@@ -872,19 +883,23 @@ The code generator tries to output shortest code possible by default.  In
 case you want beautified output, pass `--beautify` (`-b`).  Optionally you
 can pass additional arguments that control the code output:
 
-- `ascii_only` (default `false`) -- escape Unicode characters in strings and
+- `annotations` (default: `false`) — pass `true` to retain comment annotations
+  `/*@__PURE__*/` or `/*#__PURE__*/`, otherwise they will be discarded even if
+  `comments` is set.
+
+- `ascii_only` (default: `false`) — escape Unicode characters in strings and
   regexps (affects directives with non-ascii characters becoming invalid)
 
-- `beautify` (default `true`) -- whether to actually beautify the output.
+- `beautify` (default: `true`) — whether to actually beautify the output.
   Passing `-b` will set this to true, but you might need to pass `-b` even
   when you want to generate minified code, in order to specify additional
   arguments, so you can use `-b beautify=false` to override it.
 
-- `braces` (default `false`) -- always insert braces in `if`, `for`,
+- `braces` (default: `false`) — always insert braces in `if`, `for`,
   `do`, `while` or `with` statements, even if their body is a single
   statement.
 
-- `comments` (default `false`) -- pass `true` or `"all"` to preserve all
+- `comments` (default: `false`) — pass `true` or `"all"` to preserve all
   comments, `"some"` to preserve multi-line comments that contain `@cc_on`,
   `@license`, or `@preserve` (case-insensitive), a regular expression string
   (e.g. `/^!/`), or a function which returns `boolean`, e.g.
@@ -894,53 +909,53 @@ can pass additional arguments that control the code output:
   }
   ```
 
-- `galio` (default `false`) -- enable workarounds for ANT Galio bugs
+- `galio` (default: `false`) — enable workarounds for ANT Galio bugs
 
-- `indent_level` (default `4`)
+- `indent_level` (default: `4`)
 
-- `indent_start` (default `0`) -- prefix all lines by that many spaces
+- `indent_start` (default: `0`) — prefix all lines by that many spaces
 
-- `inline_script` (default `true`) -- escape HTML comments and the slash in
+- `inline_script` (default: `true`) — escape HTML comments and the slash in
   occurrences of `</script>` in strings
 
-- `keep_quoted_props` (default `false`) -- when turned on, prevents stripping
+- `keep_quoted_props` (default: `false`) — when turned on, prevents stripping
   quotes from property names in object literals.
 
-- `max_line_len` (default `false`) -- maximum line length (for uglified code)
+- `max_line_len` (default: `false`) — maximum line length (for uglified code)
 
-- `preamble` (default `null`) -- when passed it must be a string and
+- `preamble` (default: `null`) — when passed it must be a string and
   it will be prepended to the output literally.  The source map will
   adjust for this text.  Can be used to insert a comment containing
   licensing information, for example.
 
-- `preserve_line` (default `false`) -- pass `true` to retain line numbering on
+- `preserve_line` (default: `false`) — pass `true` to retain line numbering on
   a best effort basis.
 
-- `quote_keys` (default `false`) -- pass `true` to quote all keys in literal
+- `quote_keys` (default: `false`) — pass `true` to quote all keys in literal
   objects
 
-- `quote_style` (default `0`) -- preferred quote style for strings (affects
+- `quote_style` (default: `0`) — preferred quote style for strings (affects
   quoted property names and directives as well):
-  - `0` -- prefers double quotes, switches to single quotes when there are
+  - `0` — prefers double quotes, switches to single quotes when there are
     more double quotes in the string itself. `0` is best for gzip size.
-  - `1` -- always use single quotes
+  - `1` — always use single quotes
-  - `2` -- always use double quotes
+  - `2` — always use double quotes
-  - `3` -- always use the original quotes
+  - `3` — always use the original quotes
 
-- `semicolons` (default `true`) -- separate statements with semicolons.  If
+- `semicolons` (default: `true`) — separate statements with semicolons.  If
   you pass `false` then whenever possible we will use a newline instead of a
   semicolon, leading to more readable output of uglified code (size before
   gzip could be smaller; size after gzip insignificantly larger).
 
-- `shebang` (default `true`) -- preserve shebang `#!` in preamble (bash scripts)
+- `shebang` (default: `true`) — preserve shebang `#!` in preamble (bash scripts)
 
-- `width` (default `80`) -- only takes effect when beautification is on, this
+- `width` (default: `80`) — only takes effect when beautification is on, this
   specifies an (orientative) line width that the beautifier will try to
   obey.  It refers to the width of the line text (excluding indentation).
   It doesn't work very well currently, but it does make the code generated
   by UglifyJS more readable.
 
-- `wrap_iife` (default `false`) -- pass `true` to wrap immediately invoked
+- `wrap_iife` (default: `false`) — pass `true` to wrap immediately invoked
   function expressions. See
   [#640](https://github.com/mishoo/UglifyJS/issues/640) for more details.
 
@@ -1141,18 +1156,14 @@ in total it's a bit more than just using UglifyJS's own parser.
 It's not well known, but whitespace removal and symbol mangling accounts
 for 95% of the size reduction in minified code for most JavaScript - not
 elaborate code transforms. One can simply disable `compress` to speed up
-Uglify builds by 3 to 4 times. In this fast `mangle`-only mode Uglify has
+Uglify builds by 3 to 5 times.
-comparable minify speeds and gzip sizes to
-[`butternut`](https://www.npmjs.com/package/butternut):
 
 | d3.js | minify size | gzip size | minify time (seconds) |
 | --- | ---: | ---: | ---: |
-| original | 451,131 | 108,733 | - |
+| original | 511,371 | 119,932 | - |
-| uglify-js@3.0.24 mangle=false, compress=false | 316,600 | 85,245 | 0.70 |
+| uglify-js@3.13.0 mangle=false, compress=false | 363,988 | 95,695 | 0.56 |
-| uglify-js@3.0.24 mangle=true, compress=false | 220,216 | 72,730 | 1.13 |
+| uglify-js@3.13.0 mangle=true, compress=false | 253,305 | 81,281 | 0.99 |
-| butternut@0.4.6 | 217,568 | 72,738 | 1.41 |
+| uglify-js@3.13.0 mangle=true, compress=true | 244,436 | 79,854 | 5.30 |
-| uglify-js@3.0.24 mangle=true, compress=true | 212,511 | 71,560 | 3.36 |
-| babili@0.1.4 | 210,713 | 72,140 | 12.64 |
 
 To enable fast minify mode from the CLI use:
 ```
@@ -1285,3 +1296,61 @@ To allow for better optimizations, the compiler makes various assumptions:
   // SyntaxError: Identifier 'e' has already been declared
   ```
   UglifyJS may modify the input which in turn may suppress those errors.
+- Some versions of Chrome and Node.js will give incorrect results with the
+  following:
+  ```javascript
+  console.log({
+      ...{
+          set 42(v) {},
+          42: "PASS",
+      },
+  });
+  // Expected: { '42': 'PASS' }
+  // Actual:   { '42': undefined }
+  ```
+  UglifyJS may modify the input which in turn may suppress those errors.
+- Later versions of JavaScript will throw `SyntaxError` with the following:
+  ```javascript
+  var await;
+  async function f() {
+      class A {
+          static p = await;
+      }
+  }
+  // SyntaxError: Unexpected reserved word
+  ```
+  UglifyJS may modify the input which in turn may suppress those errors.
+- Later versions of JavaScript will throw `SyntaxError` with the following:
+  ```javascript
+  var async;
+  for (async of []);
+  // SyntaxError: The left-hand side of a for-of loop may not be 'async'.
+  ```
+  UglifyJS may modify the input which in turn may suppress those errors.
+- Later versions of Chrome and Node.js will give incorrect results with the
+  following:
+  ```javascript
+  console.log({
+      ...console,
+      get 42() {
+          return "FAIL";
+      },
+      [42]: "PASS",
+  }[42]);
+  // Expected: "PASS"
+  // Actual:   "FAIL"
+  ```
+  UglifyJS may modify the input which in turn may suppress those errors.
+- Earlier versions of JavaScript will throw `TypeError` with the following:
+  ```javascript
+  (function() {
+      {
+          const a = "foo";
+      }
+      {
+          const a = "bar";
+      }
+  })();
+  // TypeError: const 'a' has already been declared
+  ```
+  UglifyJS may modify the input which in turn may suppress those errors.

bin/uglifyjs

@@ -95,6 +95,8 @@ function process_option(name, no_value) {
                 "  -b, --beautify [options]                 Beautify output/specify output options.",
                 "  -O, --output-opts <options>              Output options (beautify disabled).",
                 "  -o, --output <file>                      Output file (default STDOUT).",
+                "  --annotations                            Process and preserve comment annotations.",
+                "  --no-annotations                         Ignore and discard comment annotations.",
                 "  --comments [filter]                      Preserve copyright comments in the output.",
                 "  --config-file <file>                     Read minify() options from JSON file.",
                 "  -d, --define <expr>[=value]              Global definitions.",
@@ -113,6 +115,9 @@ function process_option(name, no_value) {
                 "  --warn                                   Print warning messages.",
                 "  --webkit                                 Support non-standard Safari/Webkit.",
                 "  --wrap <name>                            Embed everything as a function with “exports” corresponding to “name” globally.",
+                "",
+                "(internal debug use only)",
+                "  --in-situ                                Warning: replaces original source files with minified output.",
                 "  --reduce-test                            Reduce a standalone test case (assumes cloned repository).",
             ].join("\n"));
         }
@@ -139,6 +144,7 @@ function process_option(name, no_value) {
       case "enclose":
         options[name] = read_value();
         break;
+      case "annotations":
       case "ie8":
       case "timings":
       case "toplevel":
@@ -146,6 +152,9 @@ function process_option(name, no_value) {
       case "webkit":
         options[name] = true;
         break;
+      case "no-annotations":
+        options.annotations = false;
+        break;
       case "keep-fnames":
         options.keep_fnames = true;
         break;
@@ -194,6 +203,7 @@ function process_option(name, no_value) {
       case "no-rename":
         options.rename = false;
         break;
+      case "in-situ":
       case "reduce-test":
       case "self":
         break;
@@ -225,10 +235,11 @@ if (options.mangle && options.mangle.properties) {
         });
     }
 }
-if (output == "ast") options.output = {
+if (/^ast|spidermonkey$/.test(output)) {
-    ast: true,
+    if (typeof options.output != "object") options.output = {};
-    code: false,
+    options.output.ast = true;
-};
+    options.output.code = false;
+}
 if (options.parse && (options.parse.acorn || options.parse.spidermonkey)
     && options.sourceMap && options.sourceMap.content == "inline") {
     fatal("inline source map only works with built-in parser");
@@ -254,7 +265,19 @@ if (specified["self"]) {
     if (!options.wrap) options.wrap = "UglifyJS";
     paths = UglifyJS.FILES;
 }
-if (paths.length) {
+if (specified["in-situ"]) {
+    if (output && output != "spidermonkey" || specified["reduce-test"] || specified["self"]) {
+        fatal("incompatible options specified");
+    }
+    paths.forEach(function(name) {
+        print(name);
+        if (/^ast|spidermonkey$/.test(name)) fatal("invalid file name specified");
+        files = {};
+        files[convert_path(name)] = read_file(name);
+        output = name;
+        run();
+    });
+} else if (paths.length) {
     simple_glob(paths).forEach(function(name) {
         files[convert_path(name)] = read_file(name);
     });
@@ -291,13 +314,43 @@ function run() {
     try {
         if (options.parse) {
             if (options.parse.acorn) {
+                var annotations = Object.create(null);
                 files = convert_ast(function(toplevel, name) {
-                    return require("acorn").parse(files[name], {
+                    var content = files[name];
+                    var list = annotations[name] = [];
+                    var prev = -1;
+                    return require("acorn").parse(content, {
+                        allowHashBang: true,
+                        ecmaVersion: "latest",
                         locations: true,
+                        onComment: function(block, text, start, end) {
+                            var match = /[@#]__PURE__/.exec(text);
+                            if (!match) {
+                                if (start != prev) return;
+                                match = [ list[prev] ];
+                            }
+                            while (/\s/.test(content[end])) end++;
+                            list[end] = match[0];
+                            prev = end;
+                        },
+                        preserveParens: true,
                         program: toplevel,
-                        sourceFile: name
+                        sourceFile: name,
+                        sourceType: "module",
                     });
                 });
+                files.walk(new UglifyJS.TreeWalker(function(node) {
+                    if (!(node instanceof UglifyJS.AST_Call)) return;
+                    var list = annotations[node.start.file];
+                    var pure = list[node.start.pos];
+                    if (!pure) {
+                        var pos = node.start.parens;
+                        if (pos) for (var i = 0; !pure && i < pos.length; i++) {
+                            pure = list[pos[i]];
+                        }
+                    }
+                    if (pure) node.pure = pure;
+                }));
             } else if (options.parse.spidermonkey) {
                 files = convert_ast(function(toplevel, name) {
                     var obj = JSON.parse(files[name]);
@@ -389,16 +442,19 @@ function run() {
             return value;
         }, 2));
     } else if (output == "spidermonkey") {
-        print(JSON.stringify(UglifyJS.minify(result.code, {
+        print(JSON.stringify(result.ast.to_mozilla_ast(), null, 2));
-            compress: false,
-            mangle: false,
-            output: {
-                ast: true,
-                code: false
-            },
-        }).ast.to_mozilla_ast(), null, 2));
     } else if (output) {
-        fs.writeFileSync(output, result.code);
+        var code;
+        if (result.ast) {
+            var opts = {};
+            for (var name in options.output) {
+                if (!/^ast|code$/.test(name)) opts[name] = options.output[name];
+            }
+            code = UglifyJS.AST_Node.from_mozilla_ast(result.ast.to_mozilla_ast()).print_to_string(opts);
+        } else {
+            code = result.code;
+        }
+        fs.writeFileSync(output, code);
         if (result.map) fs.writeFileSync(output + ".map", result.map);
     } else {
         print(result.code);

lib/ast.js

@@ -55,9 +55,10 @@ function DEFNODE(type, props, methods, base) {
     props.forEach(function(prop) {
         code.push("this.", prop, "=props.", prop, ";");
     });
+    code.push("}");
     var proto = base && new base;
     if (proto && proto.initialize || methods && methods.initialize) code.push("this.initialize();");
-    code.push("}}");
+    code.push("}");
     var ctor = new Function(code.join(""))();
     if (proto) {
         ctor.prototype = proto;
@@ -139,7 +140,7 @@ var AST_Node = DEFNODE("Node", "start end", {
 }, null);
 
 (AST_Node.log_function = function(fn, verbose) {
-    if (!fn) {
+    if (typeof fn != "function") {
         AST_Node.info = AST_Node.warn = noop;
         return;
     }
@@ -260,9 +261,9 @@ var AST_BlockScope = DEFNODE("BlockScope", "enclosed functions make_def parent_s
     $documentation: "Base class for all statements introducing a lexical scope",
     $propdoc: {
         enclosed: "[SymbolDef*/S] a list of all symbol definitions that are accessed from this scope or any subscopes",
-        functions: "[Object/S] like `variables`, but only lists function declarations",
+        functions: "[Dictionary/S] like `variables`, but only lists function declarations",
         parent_scope: "[AST_Scope?/S] link to the parent scope",
-        variables: "[Object/S] a map of name ---> SymbolDef for all variables/functions defined in this scope",
+        variables: "[Dictionary/S] a map of name ---> SymbolDef for all variables/functions defined in this scope",
     },
     clone: function(deep) {
         var node = this._clone(deep);
@@ -505,7 +506,7 @@ var AST_Scope = DEFNODE("Scope", "uses_eval uses_with", {
 var AST_Toplevel = DEFNODE("Toplevel", "globals", {
     $documentation: "The toplevel scope",
     $propdoc: {
-        globals: "[Object/S] a map of name ---> SymbolDef for all undeclared names",
+        globals: "[Dictionary/S] a map of name ---> SymbolDef for all undeclared names",
     },
     wrap: function(name) {
         var body = this.body;
@@ -874,6 +875,7 @@ var AST_ClassMethod = DEFNODE("ClassMethod", null, {
     $documentation: "A `class` method",
     _validate: function() {
         if (!(this.value instanceof AST_LambdaExpression)) throw new Error("value must be AST_LambdaExpression");
+        if (is_arrow(this.value)) throw new Error("value cannot be AST_Arrow or AST_AsyncArrow");
         if (this.value.name != null) throw new Error("name of class method's lambda must be null");
     },
 }, AST_ClassProperty);
@@ -1291,11 +1293,13 @@ function must_be_expressions(node, prop, allow_spread, allow_hole) {
     });
 }
 
-var AST_Call = DEFNODE("Call", "expression args pure", {
+var AST_Call = DEFNODE("Call", "args expression optional pure", {
     $documentation: "A function call expression",
     $propdoc: {
+        args: "[AST_Node*] array of arguments",
         expression: "[AST_Node] expression to invoke as function",
-        args: "[AST_Node*] array of arguments"
+        optional: "[boolean] whether the expression is optional chaining",
+        pure: "[string/S] marker for side-effect-free call expression",
     },
     walk: function(visitor) {
         var node = this;
@@ -1313,7 +1317,10 @@ var AST_Call = DEFNODE("Call", "expression args pure", {
 });
 
 var AST_New = DEFNODE("New", null, {
-    $documentation: "An object instantiation.  Derives from a function call since it has exactly the same properties"
+    $documentation: "An object instantiation.  Derives from a function call since it has exactly the same properties",
+    _validate: function() {
+        if (this.optional) throw new Error("optional must be false");
+    },
 }, AST_Call);
 
 var AST_Sequence = DEFNODE("Sequence", "expressions", {
@@ -1335,11 +1342,12 @@ var AST_Sequence = DEFNODE("Sequence", "expressions", {
     },
 });
 
-var AST_PropAccess = DEFNODE("PropAccess", "expression property", {
+var AST_PropAccess = DEFNODE("PropAccess", "expression optional property", {
     $documentation: "Base class for property access expressions, i.e. `a.foo` or `a[\"foo\"]`",
     $propdoc: {
         expression: "[AST_Node] the “container” expression",
-        property: "[AST_Node|string] the property to access.  For AST_Dot this is always a plain string, while for AST_Sub it's an arbitrary AST_Node"
+        optional: "[boolean] whether the expression is optional chaining",
+        property: "[AST_Node|string] the property to access.  For AST_Dot this is always a plain string, while for AST_Sub it's an arbitrary AST_Node",
     },
     getProperty: function() {
         var p = this.property;
@@ -1683,6 +1691,8 @@ var AST_ObjectMethod = DEFNODE("ObjectMethod", null, {
     $documentation: "A key(){} object property",
     _validate: function() {
         if (!(this.value instanceof AST_LambdaExpression)) throw new Error("value must be AST_LambdaExpression");
+        if (is_arrow(this.value)) throw new Error("value cannot be AST_Arrow or AST_AsyncArrow");
+        if (this.value.name != null) throw new Error("name of object method's lambda must be null");
     },
 }, AST_ObjectKeyVal);
 
@@ -1809,10 +1819,20 @@ var AST_Super = DEFNODE("Super", null, {
 var AST_This = DEFNODE("This", null, {
     $documentation: "The `this` symbol",
     _validate: function() {
-        if (this.name !== "this") throw new Error('name must be "this"');
+        if (this.TYPE == "This" && this.name !== "this") throw new Error('name must be "this"');
     },
 }, AST_ObjectIdentity);
 
+var AST_NewTarget = DEFNODE("NewTarget", null, {
+    $documentation: "The `new.target` symbol",
+    initialize: function() {
+        this.name = "new.target";
+    },
+    _validate: function() {
+        if (this.name !== "new.target") throw new Error('name must be "new.target": ' + this.name);
+    },
+}, AST_This);
+
 var AST_Template = DEFNODE("Template", "expressions strings tag", {
     $documentation: "A template literal, i.e. tag`str1${expr1}...strN${exprN}strN+1`",
     $propdoc: {

lib/minify.js

@@ -47,14 +47,12 @@ function parse_source_map(content) {
 }
 
 function set_shorthand(name, options, keys) {
-    if (options[name]) {
     keys.forEach(function(key) {
         if (options[key]) {
             if (typeof options[key] != "object") options[key] = {};
             if (!(name in options[key])) options[key][name] = options[name];
         }
     });
-    }
 }
 
 function init_cache(cache) {
@@ -75,6 +73,7 @@ function to_json(cache) {
 function minify(files, options) {
     try {
         options = defaults(options, {
+            annotations: undefined,
             compress: {},
             enclose: false,
             ie8: false,
@@ -94,17 +93,14 @@ function minify(files, options) {
             wrap: false,
         }, true);
         if (options.validate) AST_Node.enable_validation();
-        var timings = options.timings && {
+        var timings = options.timings && { start: Date.now() };
-            start: Date.now()
+        if (options.rename === undefined) options.rename = options.compress && options.mangle;
-        };
+        if (options.annotations !== undefined) set_shorthand("annotations", options, [ "compress", "output" ]);
-        if (options.rename === undefined) {
+        if (options.ie8) set_shorthand("ie8", options, [ "compress", "mangle", "output" ]);
-            options.rename = options.compress && options.mangle;
+        if (options.keep_fnames) set_shorthand("keep_fnames", options, [ "compress", "mangle" ]);
-        }
+        if (options.toplevel) set_shorthand("toplevel", options, [ "compress", "mangle" ]);
-        set_shorthand("ie8", options, [ "compress", "mangle", "output" ]);
+        if (options.v8) set_shorthand("v8", options, [ "mangle", "output" ]);
-        set_shorthand("keep_fnames", options, [ "compress", "mangle" ]);
+        if (options.webkit) set_shorthand("webkit", options, [ "mangle", "output" ]);
-        set_shorthand("toplevel", options, [ "compress", "mangle" ]);
-        set_shorthand("v8", options, [ "mangle", "output" ]);
-        set_shorthand("webkit", options, [ "mangle", "output" ]);
         var quoted_props;
         if (options.mangle) {
             options.mangle = defaults(options.mangle, {
@@ -208,27 +204,29 @@ function minify(files, options) {
         if (options.mangle && options.mangle.properties) mangle_properties(toplevel, options.mangle.properties);
         if (timings) timings.output = Date.now();
         var result = {};
-        if (options.output.ast) {
+        var output = defaults(options.output, {
-            result.ast = toplevel;
+            ast: false,
-        }
+            code: true,
-        if (!HOP(options.output, "code") || options.output.code) {
+        });
+        if (output.ast) result.ast = toplevel;
+        if (output.code) {
             if (options.sourceMap) {
-                options.output.source_map = SourceMap(options.sourceMap);
+                output.source_map = SourceMap(options.sourceMap);
                 if (options.sourceMap.includeSources) {
                     if (files instanceof AST_Toplevel) {
                         throw new Error("original source content unavailable");
                     } else for (var name in files) if (HOP(files, name)) {
-                        options.output.source_map.setSourceContent(name, files[name]);
+                        output.source_map.setSourceContent(name, files[name]);
                     }
                 }
             }
-            delete options.output.ast;
+            delete output.ast;
-            delete options.output.code;
+            delete output.code;
-            var stream = OutputStream(options.output);
+            var stream = OutputStream(output);
             toplevel.print(stream);
             result.code = stream.get();
             if (options.sourceMap) {
-                result.map = options.output.source_map.toString();
+                result.map = output.source_map.toString();
                 var url = options.sourceMap.url;
                 if (url) {
                     result.code = result.code.replace(/\n\/\/# sourceMappingURL=\S+\s*$/, "");

lib/output.js

@@ -49,9 +49,8 @@ function is_some_comments(comment) {
 }
 
 function OutputStream(options) {
-
-    var readonly = !options;
     options = defaults(options, {
+        annotations      : false,
         ascii_only       : false,
         beautify         : false,
         braces           : false,
@@ -102,12 +101,35 @@ function OutputStream(options) {
         }
     }
 
-    var indentation = options.indent_start;
     var current_col = 0;
     var current_line = 1;
     var current_pos = 0;
-    var OUTPUT = "";
+    var indentation = options.indent_start;
+    var last;
+    var line_end = 0;
+    var line_fixed = true;
+    var mappings = options.source_map && [];
+    var mapping_name;
+    var mapping_token;
+    var might_need_space;
+    var might_need_semicolon;
+    var need_newline_indented = false;
+    var need_space = false;
+    var newline_insert = -1;
+    var stack;
+    var OUTPUT;
 
+    function reset() {
+        last = "";
+        might_need_space = false;
+        might_need_semicolon = false;
+        stack = [];
+        var str = OUTPUT;
+        OUTPUT = "";
+        return str;
+    }
+
+    reset();
     var to_utf8 = options.ascii_only ? function(str, identifier) {
         if (identifier) str = str.replace(/[\ud800-\udbff][\udc00-\udfff]/g, function(ch) {
             return "\\u{" + (ch.charCodeAt(0) - 0xd7c0 << 10 | ch.charCodeAt(1) - 0xdc00).toString(16) + "}";
@@ -140,6 +162,25 @@ function OutputStream(options) {
         return j == 0 ? str : s + str.slice(j);
     };
 
+    function quote_single(str) {
+        return "'" + str.replace(/\x27/g, "\\'") + "'";
+    }
+
+    function quote_double(str) {
+        return '"' + str.replace(/\x22/g, '\\"') + '"';
+    }
+
+    var quote_string = [
+        null,
+        quote_single,
+        quote_double,
+        function(str, quote) {
+            return quote == "'" ? quote_single(str) : quote_double(str);
+        },
+    ][options.quote_style] || function(str, quote, dq, sq) {
+        return dq > sq ? quote_single(str) : quote_double(str);
+    };
+
     function make_string(str, quote) {
         var dq = 0, sq = 0;
         str = str.replace(/[\\\b\f\n\r\v\t\x22\x27\u2028\u2029\0\ufeff]/g, function(s, i) {
@@ -161,54 +202,11 @@ function OutputStream(options) {
             }
             return s;
         });
-        function quote_single() {
+        return quote_string(to_utf8(str), quote, dq, sq);
-            return "'" + str.replace(/\x27/g, "\\'") + "'";
-        }
-        function quote_double() {
-            return '"' + str.replace(/\x22/g, '\\"') + '"';
-        }
-        str = to_utf8(str);
-        switch (options.quote_style) {
-          case 1:
-            return quote_single();
-          case 2:
-            return quote_double();
-          case 3:
-            return quote == "'" ? quote_single() : quote_double();
-          default:
-            return dq > sq ? quote_single() : quote_double();
-        }
-    }
-
-    function encode_string(str, quote) {
-        var ret = make_string(str, quote);
-        if (options.inline_script) {
-            ret = ret.replace(/<\x2f(script)([>\/\t\n\f\r ])/gi, "<\\/$1$2");
-            ret = ret.replace(/\x3c!--/g, "\\x3c!--");
-            ret = ret.replace(/--\x3e/g, "--\\x3e");
-        }
-        return ret;
-    }
-
-    function make_name(name) {
-        name = name.toString();
-        name = to_utf8(name, true);
-        return name;
     }
 
     /* -----[ beautification/minification ]----- */
 
-    var has_parens = false;
-    var line_end = 0;
-    var line_fixed = true;
-    var might_need_space = false;
-    var might_need_semicolon = false;
-    var need_newline_indented = false;
-    var need_space = false;
-    var newline_insert = -1;
-    var last = "";
-    var mapping_token, mapping_name, mappings = options.source_map && [];
-
     var adjust_mappings = mappings ? function(line, col) {
         mappings.forEach(function(mapping) {
             mapping.line += line;
@@ -256,8 +254,14 @@ function OutputStream(options) {
 
     var requireSemicolonChars = makePredicate("( [ + * / - , .");
 
-    function print(str) {
+    var print = options.beautify
-        str = String(str);
+        || options.comments
+        || options.max_line_len
+        || options.preserve_line
+        || options.shebang
+        || !options.semicolons
+        || options.source_map
+        || options.width ? function(str) {
         var ch = str.charAt(0);
         if (need_newline_indented && ch) {
             need_newline_indented = false;
@@ -327,7 +331,6 @@ function OutputStream(options) {
         }
 
         OUTPUT += str;
-        has_parens = str.slice(-1) == "(";
         current_pos += str.length;
         var a = str.split(/\r?\n/), n = a.length - 1;
         current_line += n;
@@ -337,7 +340,30 @@ function OutputStream(options) {
             current_col = a[n].length;
         }
         last = str;
+    } : function(str) {
+        var ch = str.charAt(0);
+        var prev = last.slice(-1);
+        if (might_need_semicolon) {
+            might_need_semicolon = false;
+            if (prev == ":" && ch == "}" || (!ch || ";}".indexOf(ch) < 0) && prev != ";") {
+                OUTPUT += ";";
+                might_need_space = false;
             }
+        }
+        if (might_need_space) {
+            if (is_identifier_char(prev) && (is_identifier_char(ch) || ch == "\\")
+                || (ch == "/" && ch == prev)
+                || ((ch == "+" || ch == "-") && ch == last)
+                || str == "--" && last == "!"
+                || str == "in" && prev == "/"
+                || last == "--" && ch == ">") {
+                OUTPUT += " ";
+            }
+            if (prev != "<" || str != "!") might_need_space = false;
+        }
+        OUTPUT += str;
+        last = str;
+    };
 
     var space = options.beautify ? function() {
         print(" ");
@@ -346,17 +372,16 @@ function OutputStream(options) {
     };
 
     var indent = options.beautify ? function(half) {
+        if (need_newline_indented) print("\n");
         print(repeat_string(" ", half ? indentation - (options.indent_level >> 1) : indentation));
     } : noop;
 
-    var with_indent = options.beautify ? function(col, cont) {
+    var with_indent = options.beautify ? function(cont) {
-        if (col === true) col = next_indent();
         var save_indentation = indentation;
-        indentation = col;
+        indentation += options.indent_level;
-        var ret = cont();
+        cont();
         indentation = save_indentation;
-        return ret;
+    } : function(cont) { cont() };
-    } : function(col, cont) { return cont() };
 
     var may_add_newline = options.max_line_len || options.preserve_line ? function() {
         fix_line();
@@ -385,41 +410,28 @@ function OutputStream(options) {
         print(";");
     }
 
-    function next_indent() {
-        return indentation + options.indent_level;
-    }
-
     function with_block(cont) {
-        var ret;
         print("{");
         newline();
-        with_indent(next_indent(), function() {
+        with_indent(cont);
-            ret = cont();
-        });
         indent();
         print("}");
-        return ret;
     }
 
     function with_parens(cont) {
         print("(");
         may_add_newline();
-        //XXX: still nice to have that for argument lists
+        cont();
-        //var ret = with_indent(current_col, cont);
-        var ret = cont();
         may_add_newline();
         print(")");
-        return ret;
     }
 
     function with_square(cont) {
         print("[");
         may_add_newline();
-        //var ret = with_indent(current_col, cont);
+        cont();
-        var ret = cont();
         may_add_newline();
         print("]");
-        return ret;
     }
 
     function comma() {
@@ -449,31 +461,58 @@ function OutputStream(options) {
         return /^ *$/.test(OUTPUT.slice(index + 1));
     }
 
+    function pad_comment(token, force) {
+        if (need_newline_indented) return;
+        if (token.nlb && (force || !has_nlb())) {
+            need_newline_indented = true;
+        } else if (force) {
+            need_space = true;
+        }
+    }
+
+    function print_comment(comment) {
+        var value = comment.value.replace(/[@#]__PURE__/g, " ");
+        if (/^\s*$/.test(value) && !/^\s*$/.test(comment.value)) return false;
+        if (/comment[134]/.test(comment.type)) {
+            print("//" + value);
+            need_newline_indented = true;
+        } else if (comment.type == "comment2") {
+            print("/*" + value + "*/");
+        }
+        return true;
+    }
+
+    function should_merge_comments(node, parent) {
+        if (parent instanceof AST_Binary) return parent.left === node;
+        if (parent.TYPE == "Call") return parent.expression === node;
+        if (parent instanceof AST_Conditional) return parent.condition === node;
+        if (parent instanceof AST_Dot) return parent.expression === node;
+        if (parent instanceof AST_Exit) return true;
+        if (parent instanceof AST_Sequence) return parent.expressions[0] === node;
+        if (parent instanceof AST_Sub) return parent.expression === node;
+        if (parent instanceof AST_UnaryPostfix) return true;
+        if (parent instanceof AST_Yield) return true;
+    }
+
     function prepend_comments(node) {
         var self = this;
-        var scan = node instanceof AST_Exit && node.value;
+        var scan;
+        if (node instanceof AST_Exit) {
+            scan = node.value;
+        } else if (node instanceof AST_Yield) {
+            scan = node.expression;
+        }
         var comments = dump(node);
         if (!comments) comments = [];
 
         if (scan) {
             var tw = new TreeWalker(function(node) {
-                var parent = tw.parent();
+                if (!should_merge_comments(node, tw.parent())) return true;
-                if (parent instanceof AST_Exit
-                    || parent instanceof AST_Binary && parent.left === node
-                    || parent.TYPE == "Call" && parent.expression === node
-                    || parent instanceof AST_Conditional && parent.condition === node
-                    || parent instanceof AST_Dot && parent.expression === node
-                    || parent instanceof AST_Sequence && parent.expressions[0] === node
-                    || parent instanceof AST_Sub && parent.expression === node
-                    || parent instanceof AST_UnaryPostfix) {
                 var before = dump(node);
                 if (before) comments = comments.concat(before);
-                } else {
-                    return true;
-                }
             });
             tw.push(node);
-            node.value.walk(tw);
+            scan.walk(tw);
         }
 
         if (current_pos == 0) {
@@ -488,35 +527,12 @@ function OutputStream(options) {
         }
 
         comments = comments.filter(comment_filter, node);
-        if (comments.length == 0) return;
+        var printed = false;
-        var last_nlb = has_nlb();
+        comments.forEach(function(comment, index) {
-        comments.forEach(function(c, i) {
+            pad_comment(comment, index);
-            if (!last_nlb) {
+            if (print_comment(comment)) printed = true;
-                if (c.nlb) {
-                    print("\n");
-                    indent();
-                    last_nlb = true;
-                } else if (i > 0) {
-                    space();
-                }
-            }
-            if (/comment[134]/.test(c.type)) {
-                print("//" + c.value.replace(/[@#]__PURE__/g, " ") + "\n");
-                indent();
-                last_nlb = true;
-            } else if (c.type == "comment2") {
-                print("/*" + c.value.replace(/[@#]__PURE__/g, " ") + "*/");
-                last_nlb = false;
-            }
         });
-        if (!last_nlb) {
+        if (printed) pad_comment(node.start, true);
-            if (node.start.nlb) {
-                print("\n");
-                indent();
-            } else {
-                space();
-            }
-        }
 
         function dump(node) {
             var token = node.start;
@@ -546,38 +562,21 @@ function OutputStream(options) {
         }))) return;
         comments._dumped = self;
         var insert = OUTPUT.length;
-        comments.filter(comment_filter, node).forEach(function(c, i) {
+        comments.filter(comment_filter, node).forEach(function(comment, index) {
-            need_space = false;
+            pad_comment(comment, index || !tail);
-            if (need_newline_indented) {
+            print_comment(comment);
-                print("\n");
-                indent();
-                need_newline_indented = false;
-            } else if (c.nlb && (i > 0 || !has_nlb())) {
-                print("\n");
-                indent();
-            } else if (i > 0 || !tail) {
-                space();
-            }
-            if (/comment[134]/.test(c.type)) {
-                print("//" + c.value.replace(/[@#]__PURE__/g, " "));
-                need_newline_indented = true;
-            } else if (c.type == "comment2") {
-                print("/*" + c.value.replace(/[@#]__PURE__/g, " ") + "*/");
-                need_space = true;
-            }
         });
         if (OUTPUT.length > insert) newline_insert = insert;
     }
 
-    var stack = [];
     return {
         get             : get,
-        toString        : get,
+        reset           : reset,
         indent          : indent,
-        should_break    : readonly ? noop : function() {
+        should_break    : options.width ? function() {
-            return options.width && current_col - indentation >= options.width;
+            return current_col - indentation >= options.width;
-        },
+        } : return_false,
-        has_parens      : function() { return has_parens },
+        has_parens      : function() { return last.slice(-1) == "(" },
         newline         : newline,
         print           : print,
         space           : space,
@@ -587,20 +586,21 @@ function OutputStream(options) {
         semicolon       : semicolon,
         force_semicolon : force_semicolon,
         to_utf8         : to_utf8,
-        print_name      : function(name) { print(make_name(name)) },
+        print_name      : function(name) { print(to_utf8(name.toString(), true)) },
-        print_string    : function(str, quote) { print(encode_string(str, quote)) },
+        print_string    : options.inline_script ? function(str, quote) {
-        next_indent     : next_indent,
+            str = make_string(str, quote).replace(/<\x2f(script)([>\/\t\n\f\r ])/gi, "<\\/$1$2");
+            print(str.replace(/\x3c!--/g, "\\x3c!--").replace(/--\x3e/g, "--\\x3e"));
+        } : function(str, quote) {
+            print(make_string(str, quote));
+        },
         with_indent     : with_indent,
         with_block      : with_block,
         with_parens     : with_parens,
         with_square     : with_square,
         add_mapping     : add_mapping,
         option          : function(opt) { return options[opt] },
-        prepend_comments: readonly ? noop : prepend_comments,
+        prepend_comments: options.comments || options.shebang ? prepend_comments : noop,
-        append_comments : readonly || comment_filter === return_false ? noop : append_comments,
+        append_comments : options.comments ? append_comments : noop,
-        line            : function() { return current_line },
-        col             : function() { return current_col },
-        pos             : function() { return current_pos },
         push_node       : function(node) { stack.push(node) },
         pop_node        : options.preserve_line ? function() {
             var node = stack.pop();
@@ -645,10 +645,19 @@ function OutputStream(options) {
             stream.append_comments(self);
         }
     });
+    var readonly = OutputStream({
+        inline_script: false,
+        shebang: false,
+        width: false,
+    });
     AST_Node.DEFMETHOD("print_to_string", function(options) {
-        var s = OutputStream(options);
+        if (options) {
-        this.print(s);
+            var stream = OutputStream(options);
-        return s.get();
+            this.print(stream);
+            return stream.get();
+        }
+        this.print(readonly);
+        return readonly.reset();
     });
 
     /* -----[ PARENTHESES ]----- */
@@ -700,6 +709,8 @@ function OutputStream(options) {
         // (x++)[y]
         // (typeof x).y
         if (p instanceof AST_PropAccess) return p.expression === this;
+        // (~x)`foo`
+        if (p instanceof AST_Template) return p.tag === this;
     }
     PARENS(AST_Await, needs_parens_unary);
     PARENS(AST_Unary, needs_parens_unary);
@@ -741,6 +752,8 @@ function OutputStream(options) {
             || p instanceof AST_PropAccess && p.expression === this
             // ...(foo, bar, baz)
             || p instanceof AST_Spread
+            // (foo, bar)`baz`
+            || p instanceof AST_Template && p.tag === this
             // !(foo, bar, baz)
             || p instanceof AST_Unary
             // var a = (1, 2), b = a + a; ---> b == 4
@@ -771,14 +784,29 @@ function OutputStream(options) {
         if (p instanceof AST_Class) return true;
         // (foo && bar)["prop"], (foo && bar).prop
         if (p instanceof AST_PropAccess) return p.expression === this;
+        // (foo && bar)``
+        if (p instanceof AST_Template) return p.tag === this;
         // typeof (foo && bar)
         if (p instanceof AST_Unary) return true;
     });
 
+    function lhs_has_optional(node, output) {
+        var p = output.parent();
+        if (p instanceof AST_PropAccess && p.expression === node && is_lhs(p, output.parent(1))) {
+            // ++(foo?.bar).baz
+            // (foo?.()).bar = baz
+            do {
+                if (node.optional) return true;
+                node = node.expression;
+            } while (node.TYPE == "Call" || node instanceof AST_PropAccess);
+        }
+    }
+
     PARENS(AST_PropAccess, function(output) {
         var node = this;
         var p = output.parent();
-        if (p instanceof AST_New && p.expression === node) {
+        if (p instanceof AST_New) {
+            if (p.expression !== node) return false;
             // i.e. new (foo().bar)
             //
             // if there's one call into this subtree, then we need
@@ -790,20 +818,22 @@ function OutputStream(options) {
             } while (node instanceof AST_PropAccess);
             return node.TYPE == "Call";
         }
+        return lhs_has_optional(node, output);
     });
 
     PARENS(AST_Call, function(output) {
+        var node = this;
         var p = output.parent();
-        if (p instanceof AST_New) return p.expression === this;
+        if (p instanceof AST_New) return p.expression === node;
         // https://bugs.webkit.org/show_bug.cgi?id=123506
-        if (output.option("webkit")) {
+        if (output.option("webkit")
-            var g = output.parent(1);
+            && node.expression instanceof AST_Function
-            return this.expression instanceof AST_Function
             && p instanceof AST_PropAccess
-                && p.expression === this
+            && p.expression === node) {
-                && g instanceof AST_Assign
+            var g = output.parent(1);
-                && g.left === p;
+            if (g instanceof AST_Assign && g.left === p) return true;
         }
+        return lhs_has_optional(node, output);
     });
 
     PARENS(AST_New, function(output) {
@@ -929,7 +959,7 @@ function OutputStream(options) {
     });
     function print_braced_empty(self, output) {
         output.print("{");
-        output.with_indent(output.next_indent(), function() {
+        output.with_indent(function() {
             output.append_comments(self, true);
         });
         output.print("}");
@@ -1436,6 +1466,17 @@ function OutputStream(options) {
     });
 
     /* -----[ other expressions ]----- */
+    function print_annotation(self, output) {
+        if (!output.option("annotations")) return;
+        if (!self.pure) return;
+        var level = 0, parent = self, node;
+        do {
+            node = parent;
+            parent = output.parent(level++);
+            if (parent instanceof AST_Call && parent.expression === node) return;
+        } while (parent instanceof AST_PropAccess && parent.expression === node);
+        output.print(typeof self.pure == "string" ? "/*" + self.pure + "*/" : "/*@__PURE__*/");
+    }
     function print_call_args(self, output) {
         if (self.expression instanceof AST_Call || self.expression instanceof AST_Lambda) {
             output.add_mapping(self.start);
@@ -1448,11 +1489,15 @@ function OutputStream(options) {
         });
     }
     DEFPRINT(AST_Call, function(output) {
-        this.expression.print(output);
+        var self = this;
-        print_call_args(this, output);
+        print_annotation(self, output);
+        self.expression.print(output);
+        if (self.optional) output.print("?.");
+        print_call_args(self, output);
     });
     DEFPRINT(AST_New, function(output) {
         var self = this;
+        print_annotation(self, output);
         output.print("new");
         output.space();
         self.expression.print(output);
@@ -1476,26 +1521,23 @@ function OutputStream(options) {
         expr.print(output);
         var prop = self.property;
         if (output.option("ie8") && RESERVED_WORDS[prop]) {
-            output.print("[");
+            output.print(self.optional ? "?.[" : "[");
             output.add_mapping(self.end);
             output.print_string(prop);
             output.print("]");
         } else {
-            if (expr instanceof AST_Number && expr.value >= 0) {
+            if (expr instanceof AST_Number && !/[ex.)]/i.test(output.last())) output.print(".");
-                if (!/[xa-f.)]/i.test(output.last())) {
+            output.print(self.optional ? "?." : ".");
-                    output.print(".");
-                }
-            }
-            output.print(".");
             // the name after dot would be mapped about here.
             output.add_mapping(self.end);
             output.print_name(prop);
         }
     });
     DEFPRINT(AST_Sub, function(output) {
-        this.expression.print(output);
+        var self = this;
-        output.print("[");
+        self.expression.print(output);
-        this.property.print(output);
+        output.print(self.optional ? "?.[" : "[");
+        self.property.print(output);
         output.print("]");
     });
     DEFPRINT(AST_Spread, function(output) {
@@ -1588,7 +1630,14 @@ function OutputStream(options) {
             output.space();
         } : noop);
     });
-    DEFPRINT(AST_DestructuredKeyVal, print_key_value);
+    DEFPRINT(AST_DestructuredKeyVal, function(output) {
+        var self = this;
+        var key = print_property_key(self, output);
+        var value = self.value;
+        if (key && value instanceof AST_SymbolDeclaration && key == get_symbol_name(value)) return;
+        output.colon();
+        value.print(output);
+    });
     DEFPRINT(AST_DestructuredObject, function(output) {
         var props = this.properties, len = props.length, rest = this.rest;
         if (len || rest) output.with_block(function() {
@@ -1651,20 +1700,19 @@ function OutputStream(options) {
                     output.print_string(key, quote);
                 } else {
                     output.print_name(key);
+                    return key;
                 }
             } else {
                 output.print_string(key, quote);
             }
         }
     }
-
+    DEFPRINT(AST_ObjectKeyVal, function(output) {
-    function print_key_value(output) {
         var self = this;
         print_property_key(self, output);
         output.colon();
         self.value.print(output);
-    }
+    });
-    DEFPRINT(AST_ObjectKeyVal, print_key_value);
     DEFPRINT(AST_ObjectMethod, function(output) {
         print_method(this, output);
     });
@@ -1683,32 +1731,36 @@ function OutputStream(options) {
     }
     DEFPRINT(AST_ObjectGetter, print_accessor("get"));
     DEFPRINT(AST_ObjectSetter, print_accessor("set"));
-    function print_symbol(self, output) {
+    function get_symbol_name(sym) {
-        var def = self.definition();
+        var def = sym.definition();
-        output.print_name(def && def.mangled_name || self.name);
+        return def && def.mangled_name || sym.name;
     }
     DEFPRINT(AST_Symbol, function(output) {
-        print_symbol(this, output);
+        output.print_name(get_symbol_name(this));
     });
     DEFPRINT(AST_SymbolExport, function(output) {
         var self = this;
-        print_symbol(self, output);
+        var name = get_symbol_name(self);
-        if (self.alias) {
+        output.print_name(name);
+        var alias = self.alias;
+        if (alias != name) {
             output.space();
             output.print("as");
             output.space();
-            output.print_name(self.alias);
+            output.print_name(alias);
         }
     });
     DEFPRINT(AST_SymbolImport, function(output) {
         var self = this;
-        if (self.key) {
+        var name = get_symbol_name(self);
-            output.print_name(self.key);
+        var key = self.key;
+        if (key && key != name) {
+            output.print_name(key);
             output.space();
             output.print("as");
             output.space();
         }
-        print_symbol(self, output);
+        output.print_name(name);
     });
     DEFPRINT(AST_Hole, noop);
     DEFPRINT(AST_Template, function(output) {
@@ -1725,7 +1777,7 @@ function OutputStream(options) {
         output.print("`");
     });
     DEFPRINT(AST_Constant, function(output) {
-        output.print(this.value);
+        output.print("" + this.value);
     });
     DEFPRINT(AST_String, function(output) {
         output.print_string(this.value, this.quote);
@@ -1781,7 +1833,7 @@ function OutputStream(options) {
     function force_statement(stat, output) {
         if (output.option("braces") && !(stat instanceof AST_Const || stat instanceof AST_Let)) {
             make_block(stat, output);
-        } else if (!stat || stat instanceof AST_EmptyStatement) {
+        } else if (stat instanceof AST_EmptyStatement) {
             output.force_semicolon();
         } else {
             stat.print(output);
@@ -1832,11 +1884,11 @@ function OutputStream(options) {
     }
 
     function make_block(stmt, output) {
-        if (!stmt || stmt instanceof AST_EmptyStatement)
+        if (stmt instanceof AST_EmptyStatement) {
-            output.print("{}");
+            print_braced_empty(stmt, output);
-        else if (stmt instanceof AST_BlockStatement)
+        } else if (stmt instanceof AST_BlockStatement) {
             stmt.print(output);
-        else output.with_block(function() {
+        } else output.with_block(function() {
             output.indent();
             stmt.print(output);
             output.newline();
@@ -1883,7 +1935,11 @@ function OutputStream(options) {
         output.add_mapping(this.start);
     });
 
-    DEFMAP([ AST_DestructuredKeyVal, AST_ObjectProperty ], function(output) {
+    DEFMAP([
+        AST_ClassProperty,
+        AST_DestructuredKeyVal,
+        AST_ObjectProperty,
+    ], function(output) {
         if (typeof this.key == "string") output.add_mapping(this.start, this.key);
     });
 })();

lib/parse.js

@@ -100,15 +100,19 @@ var OPERATORS = makePredicate([
     "/=",
     "*=",
     "%=",
+    "**=",
     ">>=",
     "<<=",
     ">>>=",
+    "&=",
     "|=",
     "^=",
-    "&=",
     "&&",
     "||",
     "??",
+    "&&=",
+    "||=",
+    "??=",
 ]);
 
 var NEWLINE_CHARS = "\n\r\u2028\u2029";
@@ -120,7 +124,7 @@ var PUNC_AFTER_EXPRESSION = PUNC_SEPARATORS + PUNC_CLOSERS;
 var PUNC_BEFORE_EXPRESSION = PUNC_OPENERS + PUNC_SEPARATORS;
 var PUNC_CHARS = PUNC_BEFORE_EXPRESSION + "`" + PUNC_CLOSERS;
 var WHITESPACE_CHARS = NEWLINE_CHARS + " \u00a0\t\f\u000b\u200b\u2000\u2001\u2002\u2003\u2004\u2005\u2006\u2007\u2008\u2009\u200a\u202f\u205f\u3000\uFEFF";
-var NON_IDENTIFIER_CHARS = makePredicate(characters("./'\"" + OPERATOR_CHARS + PUNC_CHARS + WHITESPACE_CHARS));
+var NON_IDENTIFIER_CHARS = makePredicate(characters("./'\"#" + OPERATOR_CHARS + PUNC_CHARS + WHITESPACE_CHARS));
 
 NEWLINE_CHARS = makePredicate(characters(NEWLINE_CHARS));
 OPERATOR_CHARS = makePredicate(characters(OPERATOR_CHARS));
@@ -160,10 +164,10 @@ function decode_escape_sequence(seq) {
       case "t": return "\t";
       case "u":
         var code;
-        if (seq.length == 5) {
+        if (seq[1] == "{" && seq.slice(-1) == "}") {
-            code = seq.slice(1);
-        } else if (seq[1] == "{" && seq.slice(-1) == "}") {
             code = seq.slice(2, -1);
+        } else if (seq.length == 5) {
+            code = seq.slice(1);
         } else {
             return;
         }
@@ -347,7 +351,7 @@ function tokenizer($TEXT, filename, html5_comments, shebang) {
 
     function read_while(pred) {
         var ret = "", ch;
-        while ((ch = peek()) && pred(ch)) ret += next();
+        while ((ch = peek()) && pred(ch, ret)) ret += next();
         return ret;
     }
 
@@ -355,24 +359,27 @@ function tokenizer($TEXT, filename, html5_comments, shebang) {
         js_error(err, filename, S.tokline, S.tokcol, S.tokpos);
     }
 
+    function is_octal(num) {
+        return /^0[0-7_]+$/.test(num);
+    }
+
     function read_num(prefix) {
         var has_e = false, after_e = false, has_x = false, has_dot = prefix == ".";
-        var num = read_while(function(ch) {
+        var num = read_while(function(ch, str) {
-            var code = ch.charCodeAt(0);
+            switch (ch) {
-            switch (code) {
+              case "x": case "X":
-              case 120: case 88: // xX
                 return has_x ? false : (has_x = true);
-              case 101: case 69: // eE
+              case "e": case "E":
                 return has_x ? true : has_e ? false : (has_e = after_e = true);
-              case 43: case 45: // +-
+              case "+": case "-":
                 return after_e;
-              case (after_e = false, 46): // .
+              case (after_e = false, "."):
-                return (!has_dot && !has_x && !has_e) ? (has_dot = true) : false;
+                return has_dot || has_e || has_x || is_octal(str) ? false : (has_dot = true);
             }
-            return is_digit(code) || /[_0-9a-fo]/i.test(ch);
+            return /[_0-9a-dfo]/i.test(ch);
         });
         if (prefix) num = prefix + num;
-        if (/^0[0-7_]+$/.test(num)) {
+        if (is_octal(num)) {
             if (next_token.has_directive("use strict")) parse_error("Legacy octal literals are not allowed in strict mode");
         } else {
             num = num.replace(has_x ? /([1-9a-f]|.0)_(?=[0-9a-f])/gi : /([1-9]|.0)_(?=[0-9])/gi, "$1");
@@ -461,7 +468,7 @@ function tokenizer($TEXT, filename, html5_comments, shebang) {
     });
 
     function read_name() {
-        var backslash = false, name = "", ch, escaped = false, hex;
+        var backslash = false, ch, escaped = false, name = peek() == "#" ? next() : "";
         while (ch = peek()) {
             if (!backslash) {
                 if (ch == "\\") escaped = backslash = true, next();
@@ -476,7 +483,7 @@ function tokenizer($TEXT, filename, html5_comments, shebang) {
             }
         }
         if (KEYWORDS[name] && escaped) {
-            hex = name.charCodeAt(0).toString(16).toUpperCase();
+            var hex = name.charCodeAt(0).toString(16).toUpperCase();
             name = "\\u" + "0000".substr(hex.length) + hex + name.slice(1);
         }
         return name;
@@ -611,7 +618,7 @@ function tokenizer($TEXT, filename, html5_comments, shebang) {
             if (PUNC_CHARS[ch]) return token("punc", next());
             if (looking_at("=>")) return token("punc", next() + next());
             if (OPERATOR_CHARS[ch]) return read_operator();
-            if (code == 92 || !NON_IDENTIFIER_CHARS[ch]) return read_word();
+            if (code == 35 || code == 92 || !NON_IDENTIFIER_CHARS[ch]) return read_word();
             break;
         }
         parse_error("Unexpected character '" + ch + "'");
@@ -652,7 +659,7 @@ var UNARY_PREFIX = makePredicate("typeof void delete -- ++ ! ~ - +");
 
 var UNARY_POSTFIX = makePredicate("-- ++");
 
-var ASSIGNMENT = makePredicate("= += -= /= *= %= >>= <<= >>>= |= ^= &=");
+var ASSIGNMENT = makePredicate("= += -= /= *= %= **= >>= <<= >>>= &= |= ^= &&= ||= ??=");
 
 var PRECEDENCE = function(a, ret) {
     for (var i = 0; i < a.length;) {
@@ -850,7 +857,8 @@ function parse($TEXT, options) {
                 next();
                 return export_();
               case "import":
-                if (!is_token(peek(), "punc", "(")) {
+                var token = peek();
+                if (!(token.type == "punc" && /^[(.]$/.test(token.value))) {
                     next();
                     return import_();
                 }
@@ -1053,6 +1061,16 @@ function parse($TEXT, options) {
         return stat;
     }
 
+    function has_modifier(name) {
+        if (!is("name", name)) return;
+        var token = peek();
+        if (!token) return;
+        if (is_token(token, "operator", "=")) return;
+        if (token.type == "punc" && /^[(;}]$/.test(token.value)) return;
+        if (has_newline_before(token)) return;
+        return next();
+    }
+
     function class_(ctor) {
         var was_async = S.in_async;
         var was_gen = S.in_generator;
@@ -1078,16 +1096,8 @@ function parse($TEXT, options) {
                 continue;
             }
             var start = S.token;
-            var fixed = is("name", "static");
+            var fixed = !!has_modifier("static");
-            if (fixed) next();
+            var async = has_modifier("async");
-            var async = is("name", "async") && peek();
-            if (async) {
-                if (async.type == "punc" && /^[(=;}]$/.test(async.value) || has_newline_before(async)) {
-                    async = false;
-                } else {
-                    async = next();
-                }
-            }
             if (is("operator", "*")) {
                 next();
                 var internal = is("name") && /^#/.test(S.token.value);
@@ -1179,7 +1189,7 @@ function parse($TEXT, options) {
         var await = is("name", "await") && next();
         expect("(");
         var init = null;
-        if (!is("punc", ";")) {
+        if (await || !is("punc", ";")) {
             init = is("keyword", "const")
                 ? (next(), const_(true))
                 : is("keyword", "let")
@@ -1230,6 +1240,7 @@ function parse($TEXT, options) {
     }
 
     function for_enum(ctor, init) {
+        handle_regexp();
         var obj = expression();
         expect(")");
         return new ctor({
@@ -1485,6 +1496,7 @@ function parse($TEXT, options) {
                 body.start = start;
                 body.end = prev();
             } else {
+                handle_regexp();
                 body = expression();
                 semicolon();
             }
@@ -1502,14 +1514,14 @@ function parse($TEXT, options) {
     }
 
     function export_default_decl() {
-        switch (S.token.value) {
+        if (is("name", "async")) {
-          case "async":
             if (!is_token(peek(), "keyword", "function")) return;
             next();
             next();
             if (!is("operator", "*")) return maybe_named(AST_AsyncDefun, function_(AST_AsyncFunction));
             next();
             return maybe_named(AST_AsyncGeneratorDefun, function_(AST_AsyncGeneratorFunction));
+        } else if (is("keyword")) switch (S.token.value) {
           case "class":
             next();
             return maybe_named(AST_DefClass, class_(AST_ClassExpression));
@@ -1522,13 +1534,13 @@ function parse($TEXT, options) {
     }
 
     var export_decl = embed_tokens(function() {
-        switch (S.token.value) {
+        if (is("name", "async")) {
-          case "async":
             next();
             expect_token("keyword", "function");
             if (!is("operator", "*")) return function_(AST_AsyncDefun);
             next();
             return function_(AST_AsyncGeneratorDefun);
+        } else if (is("keyword")) switch (S.token.value) {
           case "class":
             next();
             return class_(AST_DefClass);
@@ -1734,58 +1746,66 @@ function parse($TEXT, options) {
     var new_ = function(allow_calls) {
         var start = S.token;
         expect_token("operator", "new");
-        var newexp = expr_atom(false), args;
+        var call;
+        if (is("punc", ".") && is_token(peek(), "name", "target")) {
+            next();
+            next();
+            call = new AST_NewTarget();
+        } else {
+            var exp = expr_atom(false), args;
             if (is("punc", "(")) {
                 next();
                 args = expr_list(")", !options.strict);
             } else {
                 args = [];
             }
-        var call = new AST_New({
+            call = new AST_New({ expression: exp, args: args });
-            start      : start,
+        }
-            expression : newexp,
+        call.start = start;
-            args       : args,
+        call.end = prev();
-            end        : prev()
-        });
-        mark_pure(call);
         return subscripts(call, allow_calls);
     };
 
     function as_atom_node() {
-        var tok = S.token, ret;
+        var ret, tok = S.token, value = tok.value;
         switch (tok.type) {
           case "num":
-            ret = new AST_Number({ start: tok, end: tok, value: tok.value });
+            if (isFinite(value)) {
+                ret = new AST_Number({ value: value });
+            } else {
+                ret = new AST_Infinity();
+                if (value < 0) ret = new AST_UnaryPrefix({ operator: "-", expression: ret });
+            }
             break;
           case "bigint":
-            ret = new AST_BigInt({ start: tok, end: tok, value: tok.value });
+            ret = new AST_BigInt({ value: value });
             break;
           case "string":
-            ret = new AST_String({
+            ret = new AST_String({ value : value, quote : tok.quote });
-                start : tok,
-                end   : tok,
-                value : tok.value,
-                quote : tok.quote
-            });
             break;
           case "regexp":
-            ret = new AST_RegExp({ start: tok, end: tok, value: tok.value });
+            ret = new AST_RegExp({ value: value });
             break;
           case "atom":
-            switch (tok.value) {
+            switch (value) {
               case "false":
-                ret = new AST_False({ start: tok, end: tok });
+                ret = new AST_False();
                 break;
               case "true":
-                ret = new AST_True({ start: tok, end: tok });
+                ret = new AST_True();
                 break;
               case "null":
-                ret = new AST_Null({ start: tok, end: tok });
+                ret = new AST_Null();
                 break;
+              default:
+                unexpected();
             }
             break;
+          default:
+            unexpected();
         }
         next();
+        ret.start = ret.end = tok;
         return ret;
     }
 
@@ -1825,11 +1845,13 @@ function parse($TEXT, options) {
                 expect(")");
                 var end = prev();
                 end.comments_before = ex.end.comments_before;
-                [].push.apply(ex.end.comments_after, end.comments_after);
+                end.comments_after.forEach(function(comment) {
+                    ex.end.comments_after.push(comment);
+                    if (comment.nlb) S.token.nlb = true;
+                });
                 end.comments_after.length = 0;
                 end.comments_after = ex.end.comments_after;
                 ex.end = end;
-                if (ex instanceof AST_Call) mark_pure(ex);
                 if (is("punc", "=>")) return arrow(ex instanceof AST_Sequence ? ex.expressions : [ ex ], start);
                 return subscripts(ex, allow_calls);
               case "[":
@@ -2206,19 +2228,6 @@ function parse($TEXT, options) {
         });
     }
 
-    function mark_pure(call) {
-        var start = call.start;
-        var comments = start.comments_before;
-        var i = HOP(start, "comments_before_length") ? start.comments_before_length : comments.length;
-        while (--i >= 0) {
-            var comment = comments[i];
-            if (/[@#]__PURE__/.test(comment.value)) {
-                call.pure = comment;
-                break;
-            }
-        }
-    }
-
     function template(tag) {
         var read = S.input.context().read_template;
         var strings = [];
@@ -2236,45 +2245,64 @@ function parse($TEXT, options) {
         });
     }
 
-    var subscripts = function(expr, allow_calls) {
+    var subscripts = function(expr, allow_calls, optional) {
         var start = expr.start;
-        if (is("punc", ".")) {
-            next();
-            return subscripts(new AST_Dot({
-                start      : start,
-                expression : expr,
-                property   : as_name(),
-                end        : prev()
-            }), allow_calls);
-        }
         if (is("punc", "[")) {
             next();
             var prop = expression();
             expect("]");
             return subscripts(new AST_Sub({
-                start      : start,
+                start: start,
-                expression : expr,
+                optional: optional,
-                property   : prop,
+                expression: expr,
-                end        : prev()
+                property: prop,
+                end: prev(),
             }), allow_calls);
         }
         if (allow_calls && is("punc", "(")) {
             next();
             var call = new AST_Call({
-                start      : start,
+                start: start,
-                expression : expr,
+                optional: optional,
-                args       : expr_list(")", !options.strict),
+                expression: expr,
-                end        : prev()
+                args: expr_list(")", !options.strict),
+                end: prev(),
             });
-            mark_pure(call);
             return subscripts(call, true);
         }
+        if (optional || is("punc", ".")) {
+            if (!optional) next();
+            return subscripts(new AST_Dot({
+                start: start,
+                optional: optional,
+                expression: expr,
+                property: as_name(),
+                end: prev(),
+            }), allow_calls);
+        }
         if (is("punc", "`")) {
             var tmpl = template(expr);
             tmpl.start = expr.start;
             tmpl.end = prev();
             return subscripts(tmpl, allow_calls);
         }
+        if (is("operator", "?") && is_token(peek(), "punc", ".")) {
+            next();
+            next();
+            return subscripts(expr, allow_calls, true);
+        }
+        if (expr instanceof AST_Call && !expr.pure) {
+            var start = expr.start;
+            var comments = start.comments_before;
+            var i = HOP(start, "comments_before_length") ? start.comments_before_length : comments.length;
+            while (--i >= 0) {
+                var match = /[@#]__PURE__/.exec(comments[i].value);
+                if (match) {
+                    expr.pure = match[0];
+                    break;
+                }
+            }
+        }
         return expr;
     };
 
@@ -2385,7 +2413,7 @@ function parse($TEXT, options) {
     };
 
     function is_assignable(expr) {
-        return expr instanceof AST_PropAccess || expr instanceof AST_SymbolRef;
+        return expr instanceof AST_PropAccess && !expr.optional || expr instanceof AST_SymbolRef;
     }
 
     function to_destructured(node) {
@@ -2507,7 +2535,7 @@ function parse($TEXT, options) {
         while (!is("eof"))
             body.push(statement());
         S.input.pop_directives_stack();
-        var end = prev();
+        var end = prev() || start;
         var toplevel = options.toplevel;
         if (toplevel) {
             toplevel.body = toplevel.body.concat(body);

lib/propmangle.js

@@ -81,7 +81,9 @@ var builtins = function() {
 
 function reserve_quoted_keys(ast, reserved) {
     ast.walk(new TreeWalker(function(node) {
-        if (node instanceof AST_ObjectProperty) {
+        if (node instanceof AST_ClassProperty) {
+            if (node.start && node.start.quote) add(node.key);
+        } else if (node instanceof AST_ObjectProperty) {
             if (node.start && node.start.quote) add(node.key);
         } else if (node instanceof AST_Sub) {
             addStrings(node.property, add);
@@ -163,6 +165,8 @@ function mangle_properties(ast, options) {
                 addStrings(node.args[0], add);
                 break;
             }
+        } else if (node instanceof AST_ClassProperty) {
+            if (typeof node.key == "string") add(node.key);
         } else if (node instanceof AST_Dot) {
             add(node.property);
         } else if (node instanceof AST_ObjectProperty) {
@@ -193,6 +197,8 @@ function mangle_properties(ast, options) {
                 mangleStrings(node.args[0]);
                 break;
             }
+        } else if (node instanceof AST_ClassProperty) {
+            if (typeof node.key == "string") node.key = mangle(node.key);
         } else if (node instanceof AST_Dot) {
             node.property = mangle(node.property);
         } else if (node instanceof AST_ObjectProperty) {
@@ -222,9 +228,7 @@ function mangle_properties(ast, options) {
     }
 
     function mangle(name) {
-        if (!should_mangle(name)) {
+        if (!should_mangle(name)) return name;
-            return name;
-        }
         var mangled = cache.get(name);
         if (!mangled) {
             if (debug) {
@@ -236,6 +240,7 @@ function mangle_properties(ast, options) {
             if (!mangled) do {
                 mangled = base54(++cname);
             } while (!can_mangle(mangled));
+            if (/^#/.test(name)) mangled = "#" + mangled;
             cache.set(name, mangled);
         }
         return mangled;

lib/scope.js

@@ -80,15 +80,16 @@ SymbolDef.prototype = {
         }
     },
     redefined: function() {
-        var scope = this.defun;
+        var self = this;
+        var scope = self.defun;
         if (!scope) return;
-        var name = this.name;
+        var name = self.name;
         var def = scope.variables.get(name)
             || scope instanceof AST_Toplevel && scope.globals.get(name)
-            || this.orig[0] instanceof AST_SymbolConst && find_if(function(def) {
+            || self.orig[0] instanceof AST_SymbolConst && find_if(function(def) {
                 return def.name == name;
             }, scope.enclosed);
-        if (def && def !== this) return def.redefined() || def;
+        if (def && def !== self) return def.redefined() || def;
     },
     unmangleable: function(options) {
         return this.global && !options.toplevel
@@ -96,8 +97,10 @@ SymbolDef.prototype = {
             || this.undeclared
             || !options.eval && this.scope.pinned()
             || options.keep_fnames
-                && (this.orig[0] instanceof AST_SymbolLambda
+                && (this.orig[0] instanceof AST_SymbolClass
-                    || this.orig[0] instanceof AST_SymbolDefun);
+                    || this.orig[0] instanceof AST_SymbolDefClass
+                    || this.orig[0] instanceof AST_SymbolDefun
+                    || this.orig[0] instanceof AST_SymbolLambda);
     },
 };
 
@@ -198,9 +201,10 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options) {
         } else if (node instanceof AST_SymbolConst) {
             var def = scope.def_variable(node);
             def.defun = defun;
-            def.exported = exported;
+            if (exported) def.exported = true;
         } else if (node instanceof AST_SymbolDefun) {
-            defun.def_function(node, tw.parent()).exported = exported;
+            var def = defun.def_function(node, tw.parent());
+            if (exported) def.exported = true;
             entangle(defun, scope);
         } else if (node instanceof AST_SymbolFunarg) {
             defun.def_variable(node);
@@ -209,9 +213,11 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options) {
             var def = defun.def_function(node, node.name == "arguments" ? undefined : defun);
             if (options.ie8) def.defun = defun.parent_scope.resolve();
         } else if (node instanceof AST_SymbolLet) {
-            scope.def_variable(node).exported = exported;
+            var def = scope.def_variable(node);
+            if (exported) def.exported = true;
         } else if (node instanceof AST_SymbolVar) {
-            defun.def_variable(node, node instanceof AST_SymbolImport ? undefined : null).exported = exported;
+            var def = defun.def_variable(node, node instanceof AST_SymbolImport ? undefined : null);
+            if (exported) def.exported = true;
             entangle(defun, scope);
         }
 
@@ -268,16 +274,18 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options) {
             return true;
         }
         if (node instanceof AST_SymbolDeclaration) {
+            var def = node.definition();
+            def.preinit = def.references.length;
             if (node instanceof AST_SymbolCatch) {
                 // ensure mangling works if `catch` reuses a scope variable
-                var def = node.definition().redefined();
+                var redef = def.redefined();
-                if (def) for (var s = node.scope; s; s = s.parent_scope) {
+                if (redef) for (var s = node.scope; s; s = s.parent_scope) {
-                    push_uniq(s.enclosed, def);
+                    push_uniq(s.enclosed, redef);
-                    if (s === def.scope) break;
+                    if (s === redef.scope) break;
                 }
             } else if (node instanceof AST_SymbolConst) {
                 // ensure compression works if `const` reuses a scope variable
-                var redef = node.definition().redefined();
+                var redef = def.redefined();
                 if (redef) redef.const_redefs = true;
             }
             if (node.name != "arguments") return true;
@@ -389,13 +397,14 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options) {
         } else {
             new_def = scope.def_variable(node);
         }
+        if (new_def.undeclared) self.variables.set(name, new_def);
+        if (name == "arguments" && is_arguments(old_def) && node instanceof AST_SymbolLambda) return true;
         old_def.defun = new_def.scope;
         old_def.forEach(function(node) {
             node.redef = old_def;
             node.thedef = new_def;
             node.reference(options);
         });
-        if (new_def.undeclared) self.variables.set(name, new_def);
         return true;
     }
 });
@@ -435,6 +444,7 @@ AST_Scope.DEFMETHOD("init_vars", function(parent_scope) {
 });
 AST_Arrow.DEFMETHOD("init_vars", function(parent_scope) {
     init_scope_vars(this, parent_scope);
+    return this;
 });
 AST_AsyncArrow.DEFMETHOD("init_vars", function(parent_scope) {
     init_scope_vars(this, parent_scope);
@@ -792,6 +802,7 @@ var base54 = (function() {
     var leading = init("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ$_");
     var chars, frequency;
     function reset() {
+        chars = null;
         frequency = Object.create(freq);
     }
     base54.consider = function(str, delta) {
@@ -803,19 +814,15 @@ var base54 = (function() {
         return frequency[b] - frequency[a];
     }
     base54.sort = function() {
-        chars = leading.sort(compare).concat(digits.sort(compare));
+        chars = leading.sort(compare).concat(digits).sort(compare);
     };
     base54.reset = reset;
     reset();
     function base54(num) {
-        var ret = "", base = 54;
+        var ret = leading[num % 54];
-        num++;
+        for (num = Math.floor(num / 54); --num >= 0; num >>= 6) {
-        do {
+            ret += chars[num & 0x3F];
-            num--;
+        }
-            ret += chars[num % base];
-            num = Math.floor(num / base);
-            base = 64;
-        } while (num > 0);
         return ret;
     }
     return base54;

package.json

@@ -3,7 +3,7 @@
   "description": "JavaScript parser, mangler/compressor and beautifier toolkit",
   "author": "Mihai Bazon <mihai.bazon@gmail.com> (http://lisperator.net/)",
   "license": "BSD-2-Clause",
-  "version": "3.13.0",
+  "version": "3.13.9",
   "engines": {
     "node": ">=0.8.0"
   },
@@ -23,7 +23,7 @@
     "LICENSE"
   ],
   "devDependencies": {
-    "acorn": "~7.1.0",
+    "acorn": "~8.2.1",
     "semver": "~6.3.0"
   },
   "scripts": {

test/compress.js

@@ -10,33 +10,38 @@ var sandbox = require("./sandbox");
 var semver = require("semver");
 var U = require("./node");
 
-var file = process.argv[2];
+var batch = 50;
 var dir = path.resolve(path.dirname(module.filename), "compress");
-if (file) {
+if (process.argv.length > 3) {
+    var file = process.argv[2];
+    var start = process.argv[3] | 0;
     var minify_options = require("./ufuzz/options.json").map(JSON.stringify);
-    log("--- {file}", { file: file });
     var tests = parse_test(path.resolve(dir, file));
-    process.exit(Object.keys(tests).filter(function(name) {
+    process.exit(Object.keys(tests).slice(start, start + batch).filter(function(name) {
         return !test_case(tests[name]);
     }).length);
 } else {
-    var files = fs.readdirSync(dir).filter(function(name) {
+    var files = process.argv.length == 3 ? [ process.argv[2] ] : fs.readdirSync(dir).filter(function(name) {
         return /\.js$/i.test(name);
     });
     var failures = 0;
     var failed_files = Object.create(null);
-    (function next() {
+    (function next(file, start, length) {
-        var file = files.shift();
+        if (start < length) {
-        if (file) {
+            child_process.spawn(process.argv[0], [ process.argv[1], file, start, batch ], {
-            child_process.spawn(process.argv[0], [ process.argv[1], file ], {
                 stdio: [ "ignore", 1, 2 ]
             }).on("exit", function(code) {
                 if (code) {
                     failures += code;
-                    failed_files[file] = code;
+                    failed_files[file] = true;
                 }
-                next();
+                next(file, start + batch, length);
             });
+        } else if (file = files.shift()) {
+            log("--- {file}", { file: file });
+            start = 0;
+            length = Object.keys(parse_test(path.resolve(dir, file))).length;
+            next(file, start, length);
         } else if (failures) {
             console.error();
             console.error("!!! Failed " + failures + " test case(s).");
@@ -257,6 +262,7 @@ function test_case(test) {
     var input = to_toplevel(test.input, test.mangle);
     var input_code = make_code(input);
     var input_formatted = make_code(test.input, {
+        annotations: true,
         beautify: true,
         comments: "all",
         keep_quoted_props: true,

test/compress/annotations.js

@@ -0,0 +1,474 @@
+issue_2629_1: {
+    options = {
+        annotations: true,
+        side_effects: true,
+    }
+    beautify = {
+        comments: "all",
+    }
+    input: {
+        /*@__PURE__*/ a();
+        /*@__PURE__*/ (b());
+        (/*@__PURE__*/ c)();
+        (/*@__PURE__*/ d());
+    }
+    expect_exact: "c();"
+}
+
+issue_2629_2: {
+    options = {
+        annotations: true,
+        side_effects: true,
+    }
+    beautify = {
+        comments: "all",
+    }
+    input: {
+        /*@__PURE__*/ a(1)(2)(3);
+        /*@__PURE__*/ (b(1))(2)(3);
+        /*@__PURE__*/ (c(1)(2))(3);
+        /*@__PURE__*/ (d(1)(2)(3));
+        (/*@__PURE__*/ e)(1)(2)(3);
+        (/*@__PURE__*/ f(1))(2)(3);
+        (/*@__PURE__*/ g(1)(2))(3);
+        (/*@__PURE__*/ h(1)(2)(3));
+    }
+    expect_exact: [
+        "e(1)(2)(3);",
+        "f(1)(2)(3);",
+        "g(1)(2)(3);",
+    ]
+}
+
+issue_2629_3: {
+    options = {
+        annotations: true,
+        side_effects: true,
+    }
+    beautify = {
+        comments: "all",
+    }
+    input: {
+        /*@__PURE__*/ a.x(1).y(2).z(3);
+        /*@__PURE__*/ (b.x)(1).y(2).z(3);
+        /*@__PURE__*/ (c.x(1)).y(2).z(3);
+        /*@__PURE__*/ (d.x(1).y)(2).z(3);
+        /*@__PURE__*/ (e.x(1).y(2)).z(3);
+        /*@__PURE__*/ (f.x(1).y(2).z)(3);
+        /*@__PURE__*/ (g.x(1).y(2).z(3));
+        (/*@__PURE__*/ h).x(1).y(2).z(3);
+        (/*@__PURE__*/ i.x)(1).y(2).z(3);
+        (/*@__PURE__*/ j.x(1)).y(2).z(3);
+        (/*@__PURE__*/ k.x(1).y)(2).z(3);
+        (/*@__PURE__*/ l.x(1).y(2)).z(3);
+        (/*@__PURE__*/ m.x(1).y(2).z)(3);
+        (/*@__PURE__*/ n.x(1).y(2).z(3));
+    }
+    expect_exact: [
+        "h.x(1).y(2).z(3);",
+        "i.x(1).y(2).z(3);",
+        "j.x(1).y(2).z(3);",
+        "k.x(1).y(2).z(3);",
+        "l.x(1).y(2).z(3);",
+        "m.x(1).y(2).z(3);",
+    ]
+}
+
+issue_2629_4: {
+    options = {
+        annotations: true,
+        side_effects: true,
+    }
+    input: {
+        (/*@__PURE__*/ x(), y());
+        (w(), /*@__PURE__*/ x(), y());
+    }
+    expect: {
+        y();
+        w(), y();
+    }
+}
+
+issue_2629_5: {
+    options = {
+        annotations: true,
+        side_effects: true,
+    }
+    input: {
+        [ /*@__PURE__*/ x() ];
+        [ /*@__PURE__*/ x(), y() ];
+        [ w(), /*@__PURE__*/ x(), y() ];
+    }
+    expect: {
+        y();
+        w(), y();
+    }
+}
+
+issue_2638: {
+    options = {
+        annotations: true,
+        side_effects: true,
+    }
+    beautify = {
+        comments: "all",
+    }
+    input: {
+        /*@__PURE__*/(g() || h())(x(), y());
+        (/*@__PURE__*/ (a() || b()))(c(), d());
+    }
+    expect_exact: [
+        "x(),y();",
+        "(a()||b())(c(),d());",
+    ]
+}
+
+issue_2705_1: {
+    options = {
+        annotations: true,
+        side_effects: true,
+    }
+    beautify = {
+        comments: "all",
+    }
+    input: {
+        /*@__PURE__*/ new a();
+        /*@__PURE__*/ (new b());
+        new (/*@__PURE__*/ c)();
+        (/*@__PURE__*/ new d());
+    }
+    expect_exact: [
+        "new c;",
+    ]
+}
+
+issue_2705_2: {
+    options = {
+        annotations: true,
+        side_effects: true,
+    }
+    beautify = {
+        comments: "all",
+    }
+    input: {
+        /*@__PURE__*/ new a(1)(2)(3);
+        /*@__PURE__*/ new (b(1))(2)(3);
+        /*@__PURE__*/ new (c(1)(2))(3);
+        /*@__PURE__*/ new (d(1)(2)(3));
+        new (/*@__PURE__*/ e)(1)(2)(3);
+        (/*@__PURE__*/ new f(1))(2)(3);
+        (/*@__PURE__*/ new g(1)(2))(3);
+        (/*@__PURE__*/ new h(1)(2)(3));
+    }
+    expect_exact: [
+        "new e(1)(2)(3);",
+        "new f(1)(2)(3);",
+        "new g(1)(2)(3);",
+    ]
+}
+
+issue_2705_3: {
+    options = {
+        annotations: true,
+        side_effects: true,
+    }
+    beautify = {
+        comments: "all",
+    }
+    input: {
+        /*@__PURE__*/ new a.x(1).y(2).z(3);
+        /*@__PURE__*/ new (b.x)(1).y(2).z(3);
+        /*@__PURE__*/ new (c.x(1)).y(2).z(3);
+        /*@__PURE__*/ new (d.x(1).y)(2).z(3);
+        /*@__PURE__*/ new (e.x(1).y(2)).z(3);
+        /*@__PURE__*/ new (f.x(1).y(2).z)(3);
+        /*@__PURE__*/ new (g.x(1).y(2).z(3));
+        new (/*@__PURE__*/ h).x(1).y(2).z(3);
+        /* */ new (/*@__PURE__*/ i.x)(1).y(2).z(3);
+        (/*@__PURE__*/ new j.x(1)).y(2).z(3);
+        (/*@__PURE__*/ new k.x(1).y)(2).z(3);
+        (/*@__PURE__*/ new l.x(1).y(2)).z(3);
+        (/*@__PURE__*/ new m.x(1).y(2).z)(3);
+        (/*@__PURE__*/ new n.x(1).y(2).z(3));
+    }
+    expect_exact: [
+        "new h.x(1).y(2).z(3);",
+        "/* */new i.x(1).y(2).z(3);",
+        "new j.x(1).y(2).z(3);",
+        "new k.x(1).y(2).z(3);",
+        "new l.x(1).y(2).z(3);",
+        "new m.x(1).y(2).z(3);",
+    ]
+}
+
+issue_2705_4: {
+    options = {
+        annotations: true,
+        side_effects: true,
+    }
+    input: {
+        (/*@__PURE__*/ new x(), y());
+        (w(), /*@__PURE__*/ new x(), y());
+    }
+    expect: {
+        y();
+        w(), y();
+    }
+}
+
+issue_2705_5: {
+    options = {
+        annotations: true,
+        side_effects: true,
+    }
+    input: {
+        [ /*@__PURE__*/ new x() ];
+        [ /*@__PURE__*/ new x(), y() ];
+        [ w(), /*@__PURE__*/ new x(), y() ];
+    }
+    expect: {
+        y();
+        w(), y();
+    }
+}
+
+issue_2705_6: {
+    options = {
+        annotations: true,
+        side_effects: true,
+    }
+    beautify = {
+        comments: "all",
+    }
+    input: {
+        /*@__PURE__*/new (g() || h())(x(), y());
+        /* */ new (/*@__PURE__*/ (a() || b()))(c(), d());
+    }
+    expect_exact: [
+        "x(),y();",
+        "/* */new(a()||b())(c(),d());",
+    ]
+}
+
+issue_3858: {
+    options = {
+        annotations: true,
+        collapse_vars: true,
+        inline: true,
+        keep_fargs: false,
+        unsafe: true,
+        unused: true,
+    }
+    input: {
+        var f = function(a) {
+            return /*@__PURE__*/ function(b) {
+                console.log(b);
+            }(a);
+        };
+        f("PASS");
+    }
+    expect: {
+        var f = function(a) {
+            return function() {
+                console.log(a);
+            }();
+        };
+        f("PASS");
+    }
+    expect_stdout: "PASS"
+}
+
+inline_pure_call_1: {
+    options = {
+        annotations: true,
+        collapse_vars: true,
+        inline: true,
+        keep_fargs: false,
+        reduce_vars: true,
+        sequences: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var f = function(a) {
+            return /*@__PURE__*/ function(b) {
+                console.log(b);
+            }(a);
+        };
+        f("PASS");
+    }
+    expect: {}
+}
+
+inline_pure_call_2: {
+    options = {
+        annotations: true,
+        collapse_vars: true,
+        inline: true,
+        keep_fargs: false,
+        reduce_vars: true,
+        sequences: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var f = function(a) {
+            return /*@__PURE__*/ function(b) {
+                console.log(b);
+            }(a);
+        };
+        var a = f("PASS");
+    }
+    expect: {}
+}
+
+inline_pure_call_3: {
+    options = {
+        annotations: true,
+        collapse_vars: true,
+        evaluate: true,
+        inline: true,
+        keep_fargs: false,
+        passes: 2,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var f = function(a) {
+            return /*@__PURE__*/ function(b) {
+                console.log(b);
+            }(a);
+        };
+        var a = f("PASS");
+        console.log(a);
+    }
+    expect: {
+        var a = function() {
+            console.log("PASS");
+        }();
+        console.log(a);
+    }
+    expect_stdout: [
+        "PASS",
+        "undefined",
+    ]
+}
+
+inline_pure_call_4: {
+    options = {
+        annotations: true,
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = /*@__PURE__*/ function() {
+            return console.log("PASS"), 42;
+        }();
+        console.log(a);
+    }
+    expect: {
+        var a = function() {
+            return console.log("PASS"), 42;
+        }();
+        console.log(a);
+    }
+    expect_stdout: [
+        "PASS",
+        "42",
+    ]
+}
+
+compress_and_output_annotations_enabled: {
+    options = {
+        annotations: true,
+        side_effects: true,
+    }
+    beautify = {
+        annotations: true,
+        beautify: true,
+        comments: false,
+    }
+    input: {
+        var top = /*@__PURE__*/ foo();
+        /*@__PURE__*/ a(1)(2)(3);
+        /*@__PURE__*/ (b(1))(2)(3);
+        /*@__PURE__*/ (c(1)(2))(3);
+        /*@__PURE__*/ (d(1)(2)(3));
+        (/*@__PURE__*/ e)(1)(2)(3);
+        (/*@__PURE__*/ f(1))(2)(3);
+        (/*@__PURE__*/ g(1)(2))(3);
+        (/*@__PURE__*/ h(1)(2)(3));
+        /*@__PURE__*/ l(1).p(2);
+        (/*@__PURE__*/ m(1)).p(2);
+        (/*@__PURE__*/ n(1).p)(2);
+        (/*@__PURE__*/ o(1).p(2));
+    }
+    expect_exact: [
+        "var top = /*@__PURE__*/foo();",
+        "",
+        "e(1)(2)(3);",
+        "",
+        "f(1)(2)(3);",
+        "",
+        "g(1)(2)(3);",
+        "",
+        "m(1).p(2);",
+        "",
+        "n(1).p(2);",
+    ]
+}
+
+compress_annotations_disabled_output_annotations_enabled: {
+    options = {
+        annotations: false,
+        evaluate: true,
+        sequences: true,
+        side_effects: true,
+    }
+    beautify = {
+        annotations: true,
+        comments: true,
+    }
+    input: {
+        /*@__PURE__*/ a(1+2);
+        /*#__PURE__*/ (b(2+3));
+        (/*@__PURE__*/ c)(side_effect);
+        (/*#__PURE__*/ d(effect()));
+    }
+    expect_exact: [
+        "/*@__PURE__*/a(3),",
+        "/*#__PURE__*/b(5),",
+        "c(side_effect),",
+        "/*#__PURE__*/d(effect());",
+    ]
+}
+
+compress_and_output_annotations_disabled: {
+    options = {
+        annotations: false,
+        evaluate: true,
+        sequences: true,
+        side_effects: true,
+    }
+    beautify = {
+        annotations: false,
+        comments: true,
+    }
+    input: {
+        /*@__PURE__*/ a(1+2);
+        /*@__PURE__*/ (b(2+3));
+        (/*@__PURE__*/ c)(side_effect);
+        (/*@__PURE__*/ d(effect()));
+    }
+    expect_exact: [
+        "a(3),",
+        "b(5),",
+        "c(side_effect),",
+        "d(effect());",
+    ]
+}

test/compress/arguments.js

@@ -84,6 +84,7 @@ replace_index_drop_fargs_1: {
         evaluate: true,
         keep_fargs: false,
         properties: true,
+        reduce_vars: true,
     }
     input: {
         var arguments = [];
@@ -119,7 +120,7 @@ replace_index_drop_fargs_1: {
             console.log(b, b, arguments.foo);
         })("bar", 42);
         (function(arguments) {
-            console.log(arguments[1], arguments[1], arguments.foo);
+            console.log("bar"[1], "bar"[1], "bar".foo);
         })("bar", 42);
         (function(argument_0, argument_1) {
             var arguments;
@@ -253,6 +254,25 @@ duplicate_argname: {
     expect_stdout: "bar 42 foo 42 bar"
 }
 
+fraction: {
+    options = {
+        arguments: true,
+        keep_fargs: false,
+        reduce_vars: true,
+    }
+    input: {
+        console.log(function() {
+            return arguments[0.3];
+        }("FAIL") || "PASS");
+    }
+    expect: {
+        console.log(function() {
+            return arguments[0.3];
+        }("FAIL") || "PASS");
+    }
+    expect_stdout: "PASS"
+}
+
 issue_3273: {
     options = {
         arguments: true,
@@ -649,6 +669,7 @@ issue_3420_1: {
     options = {
         arguments: true,
         keep_fargs: false,
+        reduce_vars: true,
     }
     input: {
         console.log(function() {
@@ -671,6 +692,7 @@ issue_3420_2: {
     options = {
         arguments: true,
         keep_fargs: false,
+        reduce_vars: true,
     }
     input: {
         var foo = function() {
@@ -691,6 +713,7 @@ issue_3420_3: {
     options = {
         arguments: true,
         keep_fargs: false,
+        reduce_vars: true,
     }
     input: {
         "use strict";
@@ -713,6 +736,7 @@ issue_3420_4: {
     options = {
         arguments: true,
         keep_fargs: false,
+        reduce_vars: true,
     }
     input: {
         !function() {
@@ -738,6 +762,7 @@ issue_3420_5: {
     options = {
         arguments: true,
         keep_fargs: false,
+        reduce_vars: true,
     }
     input: {
         "use strict";
@@ -765,6 +790,7 @@ issue_3420_6: {
     options = {
         arguments: true,
         keep_fargs: false,
+        reduce_vars: true,
     }
     input: {
         console.log(function() {
@@ -783,6 +809,7 @@ issue_3420_7: {
     options = {
         arguments: true,
         keep_fargs: false,
+        reduce_vars: true,
     }
     input: {
         "use strict";
@@ -827,6 +854,7 @@ issue_4291_1: {
     options = {
         arguments: true,
         keep_fargs: false,
+        reduce_vars: true,
     }
     input: {
         console.log(function() {
@@ -847,6 +875,7 @@ issue_4291_2: {
     options = {
         arguments: true,
         keep_fargs: false,
+        reduce_vars: true,
     }
     input: {
         var a = function() {
@@ -857,8 +886,8 @@ issue_4291_2: {
         console.log(a[1], a[0], a.length);
     }
     expect: {
-        var a = function(argument_0) {
+        var a = function() {
-            if (argument_0)
+            if (arguments[0])
                 arguments[1] = "PASS";
             return arguments;
         }(42);
@@ -871,6 +900,7 @@ issue_4397: {
     options = {
         arguments: true,
         keep_fargs: false,
+        reduce_vars: true,
     }
     input: {
         console.log(typeof function() {
@@ -999,3 +1029,26 @@ issue_4696: {
     }
     expect_stdout: "PASS"
 }
+
+issue_4809: {
+    options = {
+        arguments: true,
+        keep_fargs: false,
+        reduce_vars: true,
+    }
+    input: {
+        A = 0;
+        (function() {
+            arguments[A] = "PASS";
+            console.log(arguments[0]);
+        })();
+    }
+    expect: {
+        A = 0;
+        (function() {
+            arguments[A] = "PASS";
+            console.log(arguments[0]);
+        })();
+    }
+    expect_stdout: "PASS"
+}

test/compress/arrows.js

@@ -276,6 +276,7 @@ drop_arguments: {
     options = {
         arguments: true,
         keep_fargs: false,
+        reduce_vars: true,
     }
     input: {
         console.log(function() {
@@ -420,6 +421,7 @@ collapse_value: {
         arrows: true,
         collapse_vars: true,
         keep_fargs: false,
+        unsafe: true,
         unused: true,
     }
     input: {
@@ -803,3 +805,13 @@ issue_4687_2: {
     expect_stdout: "PASS"
     node_version: ">=4"
 }
+
+issue_4772: {
+    input: {
+        var f = a => (a)
+        /**/ console.log(f("PASS"));
+    }
+    expect_exact: 'var f=a=>a;console.log(f("PASS"));'
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}

test/compress/assignments.js

@@ -475,3 +475,274 @@ issue_4521: {
     }
     expect_stdout: "42"
 }
+
+logical_assignments: {
+    input: {
+        var a = 42, b = null, c;
+        a &&= "foo";
+        b ||= "bar";
+        c ??= "baz";
+        console.log(a, b, c);
+    }
+    expect_exact: 'var a=42,b=null,c;a&&="foo";b||="bar";c??="baz";console.log(a,b,c);'
+    expect_stdout: "foo bar baz"
+    node_version: ">=15"
+}
+
+logical_collapse_vars: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        var a = "FAIL", b = false;
+        a = "PASS";
+        b ??= a;
+        console.log(a);
+    }
+    expect: {
+        var a = "FAIL", b = false;
+        a = "PASS";
+        b ??= a;
+        console.log(a);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=15"
+}
+
+logical_reduce_vars: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = "PASS", b = 42;
+        b ??= a = "FAIL";
+        console.log(a);
+    }
+    expect: {
+        var a = "PASS", b = 42;
+        b ??= a = "FAIL";
+        console.log(a);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=15"
+}
+
+logical_side_effects: {
+    options = {
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = "PASS", b = 42;
+        b ??= a = "FAIL";
+        console.log(a);
+    }
+    expect: {
+        var a = "PASS", b = 42;
+        b ??= a = "FAIL";
+        console.log(a);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=15"
+}
+
+issue_4815_1: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = "PASS";
+        42..p &&= a = "FAIL";
+        console.log(a);
+    }
+    expect: {
+        var a = "PASS";
+        42..p &&= a = "FAIL";
+        console.log(a);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=15"
+}
+
+issue_4815_2: {
+    options = {
+        pure_getters: "strict",
+        side_effects: true,
+    }
+    input: {
+        var a = "PASS";
+        42..p &&= a = "FAIL";
+        console.log(a);
+    }
+    expect: {
+        var a = "PASS";
+        42..p &&= a = "FAIL";
+        console.log(a);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=15"
+}
+
+issue_4819: {
+    options = {
+        comparisons: true,
+    }
+    input: {
+        console.log(void 0 === ([].p &&= 42));
+    }
+    expect: {
+        console.log(void 0 === ([].p &&= 42));
+    }
+    expect_stdout: "true"
+    node_version: ">=15"
+}
+
+issue_4827_1: {
+    options = {
+        collapse_vars: true,
+        toplevel: true,
+    }
+    input: {
+        A = "FAIL";
+        var a = A, b = "PASS", c;
+        c &&= b = a, console.log(b);
+    }
+    expect: {
+        A = "FAIL";
+        var a = A, b = "PASS", c;
+        c &&= b = a, console.log(b);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=15"
+}
+
+issue_4827_2: {
+    options = {
+        collapse_vars: true,
+        inline: true,
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = 0, b = "PASS";
+        function f(c) {
+            a++,
+            c &&= b = a;
+        }
+        f();
+        console.log(b);
+    }
+    expect: {
+        var a = 0, b = "PASS";
+        a++,
+        c &&= b = a;
+        var c;
+        console.log(b);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=15"
+}
+
+issue_4827_3: {
+    options = {
+        merge_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var a = 0, b, c;
+        a++;
+        c &&= b = a;
+        console.log(b);
+    }
+    expect: {
+        var a = 0, b, c;
+        a++;
+        c &&= b = a;
+        console.log(b);
+    }
+    expect_stdout: "undefined"
+    node_version: ">=15"
+}
+
+issue_4876: {
+    options = {
+        pure_getters: "strict",
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+    }
+    input: {
+        try {
+            var a = null;
+            var b = a &&= 42;
+            b.p;
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect: {
+        try {
+            var a = null;
+            var b = a &&= 42;
+            b.p;
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect_stdout: "PASS"
+    node_version: ">=15"
+}
+
+issue_4924_1: {
+    options = {
+        collapse_vars: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a, b;
+        console.log("PASS");
+        a = function() {};
+        b = function() {}(b ||= a);
+    }
+    expect: {
+        var b;
+        console.log("PASS");
+        b = void (b ||= function() {});
+    }
+    expect_stdout: "PASS"
+    node_version: ">=15"
+}
+
+issue_4924_2: {
+    options = {
+        collapse_vars: true,
+        dead_code: true,
+        passes: 2,
+        sequences: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a, b;
+        console.log("PASS");
+        a = function() {};
+        b = function() {}(b ||= a);
+    }
+    expect: {
+        console.log("PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=15"
+}

test/compress/awaits.js

@@ -23,16 +23,34 @@ async_label: {
 }
 
 await_await: {
+    options = {
+        awaits: true,
+        side_effects: true,
+    }
     input: {
         (async function() {
+            await await {
+                then(resolve) {
+                    resolve({
+                        then() {
                             console.log("PASS");
-            await await 42;
+                        },
+                    });
+                },
+            };
         })();
     }
     expect: {
         (async function() {
+            await {
+                then(resolve) {
+                    resolve({
+                        then() {
                             console.log("PASS");
-            await await 42;
+                        },
+                    });
+                },
+            };
         })();
     }
     expect_stdout: "PASS"
@@ -209,9 +227,7 @@ inline_await_1_trim: {
         console.log("PASS");
     }
     expect: {
-        (async function() {
+        void 0;
-            await 0;
-        })();
         console.log("PASS");
     }
     expect_stdout: "PASS"
@@ -316,7 +332,7 @@ inline_await_3_trim: {
     }
     expect: {
         (async function() {
-            return a = "PASS", b = console.log, await b(a);
+            return a = "PASS", b = console.log, b(a);
             var a, b;
         })();
     }
@@ -539,6 +555,51 @@ collapse_property_lambda: {
     node_version: ">=8"
 }
 
+drop_async_1: {
+    options = {
+        awaits: true,
+        inline: true,
+        side_effects: true,
+    }
+    input: {
+        console.log(function(a) {
+            (async function() {
+                a *= 7;
+            })();
+            return a;
+        }(6));
+    }
+    expect: {
+        console.log(function(a) {
+            void (a *= 7);
+            return a;
+        }(6));
+    }
+    expect_stdout: "42"
+    node_version: ">=8"
+}
+
+drop_async_2: {
+    options = {
+        awaits: true,
+        collapse_vars: true,
+        evaluate: true,
+        inline: true,
+        side_effects: true,
+    }
+    input: {
+        console.log(function(a) {
+            (async b => await (a *= b))(7);
+            return a;
+        }(6));
+    }
+    expect: {
+        console.log(42);
+    }
+    expect_stdout: "42"
+    node_version: ">=8"
+}
+
 drop_return: {
     options = {
         side_effects: true,
@@ -546,7 +607,7 @@ drop_return: {
     input: {
         (async function(a) {
             while (!console);
-            return console.log(a);
+            return !console.log(a);
         })(42);
     }
     expect: {
@@ -596,14 +657,14 @@ functions: {
             async function b() {
                 return !!b;
             }
-            var c = async function(c) {
+            async function c(c) {
                 return c;
-            };
-            if (await c(await b(await a()))) {
-                async function d() {}
-                async function e() {
-                    return typeof e;
             }
+            if (await c(await b(await a()))) {
+                var d = async function() {};
+                var e = async function y() {
+                    return typeof y;
+                };
                 var f = async function(f) {
                     return f;
                 };
@@ -654,9 +715,9 @@ functions_use_strict: {
             async function b() {
                 return !!b;
             }
-            var c = async function(c) {
+            async function c(c) {
                 return c;
-            };
+            }
             if (await c(await b(await a()))) {
                 var d = async function() {};
                 var e = async function y() {
@@ -673,6 +734,54 @@ functions_use_strict: {
     node_version: ">=8"
 }
 
+functions_anonymous: {
+    options = {
+        functions: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var await = async function() {
+            console.log("PASS");
+        };
+        await(await);
+    }
+    expect: {
+        async function await() {
+            console.log("PASS");
+        }
+        await();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
+functions_inner_var: {
+    options = {
+        functions: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var await = function a() {
+            var a;
+            console.log(a, a);
+        };
+        await(await);
+    }
+    expect: {
+        function await() {
+            var a;
+            console.log(a, a);
+        }
+        await();
+    }
+    expect_stdout: "undefined undefined"
+    node_version: ">=8"
+}
+
 issue_4335_1: {
     options = {
         inline: true,
@@ -1246,3 +1355,406 @@ issue_4618: {
     expect_stdout: "function"
     node_version: ">=8"
 }
+
+issue_4717: {
+    options = {
+        inline: true,
+        reduce_vars: true,
+        sequences: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        (function() {
+            async function f() {
+                var a = function() {
+                    await;
+                }();
+                return "FAIL";
+            }
+            return f();
+        })().then(console.log).catch(function() {
+            console.log("PASS");
+        });
+    }
+    expect: {
+        (async function() {
+            return function() {
+                await;
+            }(), "FAIL";
+        })().then(console.log).catch(function() {
+            console.log("PASS");
+        });
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
+issue_4738_1: {
+    options = {
+        awaits: true,
+        side_effects: true,
+    }
+    input: {
+        (async function() {
+            await {
+                then() {
+                    console.log("PASS");
+                },
+            };
+        })();
+    }
+    expect: {
+        (async function() {
+            await {
+                then() {
+                    console.log("PASS");
+                },
+            };
+        })();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
+issue_4738_2: {
+    options = {
+        awaits: true,
+        side_effects: true,
+    }
+    input: {
+        (async function() {
+            await {
+                get then() {
+                    console.log("PASS");
+                },
+            };
+        })();
+    }
+    expect: {
+        (async function() {
+            await {
+                get then() {
+                    console.log("PASS");
+                },
+            };
+        })();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
+issue_4738_3: {
+    options = {
+        awaits: true,
+        side_effects: true,
+    }
+    input: {
+        (async function() {
+            await {
+                then: function() {
+                    console.log("PASS");
+                },
+            };
+        })();
+    }
+    expect: {
+        (async function() {
+            await {
+                then: function() {
+                    console.log("PASS");
+                },
+            };
+        })();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
+issue_4747: {
+    options = {
+        collapse_vars: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        console.log(function(a) {
+            async function f() {
+                a = "PASS";
+                null.p += "PASS";
+            }
+            f();
+            return a;
+        }("FAIL"));
+    }
+    expect: {
+        console.log(function(a) {
+            (async function() {
+                a = "PASS";
+                null.p += "PASS";
+            })();
+            return a;
+        }("FAIL"));
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
+issue_4764_1: {
+    options = {
+        side_effects: true,
+    }
+    input: {
+        (async function() {
+            return {
+                then() {
+                    console.log("PASS");
+                },
+            };
+        })();
+    }
+    expect: {
+        (async function() {
+            return {
+                then() {
+                    console.log("PASS");
+                },
+            };
+        })();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
+issue_4764_2: {
+    options = {
+        arrows: true,
+        side_effects: true,
+    }
+    input: {
+        (async () => ({
+            get then() {
+                console.log("PASS");
+            },
+        }))();
+    }
+    expect: {
+        (async () => ({
+            get then() {
+                console.log("PASS");
+            },
+        }))();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
+issue_4764_3: {
+    options = {
+        side_effects: true,
+    }
+    input: {
+        (async function(o) {
+            return o;
+        })({
+            then() {
+                console.log("PASS");
+            },
+        });
+    }
+    expect: {
+        (async function(o) {
+            return o;
+        })({
+            then() {
+                console.log("PASS");
+            },
+        });
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
+issue_4972_1: {
+    options = {
+        awaits: true,
+        side_effects: true,
+    }
+    input: {
+        console.log("foo");
+        (async function() {
+            try {
+                return await "bar";
+            } finally {
+                console.log("baz");
+            }
+        })().then(console.log);
+        console.log("moo");
+    }
+    expect: {
+        console.log("foo");
+        (async function() {
+            try {
+                return await "bar";
+            } finally {
+                console.log("baz");
+            }
+        })().then(console.log);
+        console.log("moo");
+    }
+    expect_stdout: [
+        "foo",
+        "moo",
+        "baz",
+        "bar",
+    ]
+    node_version: ">=8"
+}
+
+issue_4972_2: {
+    options = {
+        awaits: true,
+        side_effects: true,
+    }
+    input: {
+        console.log("foo");
+        (async function() {
+            try {
+                console.log("bar");
+            } finally {
+                return await "baz";
+            }
+        })().then(console.log);
+        console.log("moo");
+    }
+    expect: {
+        console.log("foo");
+        (async function() {
+            try {
+                console.log("bar");
+            } finally {
+                return "baz";
+            }
+        })().then(console.log);
+        console.log("moo");
+    }
+    expect_stdout: [
+        "foo",
+        "bar",
+        "moo",
+        "baz",
+    ]
+    node_version: ">=8"
+}
+
+issue_4972_3: {
+    options = {
+        awaits: true,
+        side_effects: true,
+    }
+    input: {
+        console.log("foo");
+        try {
+            (async function() {
+                return await "bar";
+            })().then(console.log);
+        } finally {
+            console.log("baz");
+        }
+        console.log("moo");
+    }
+    expect: {
+        console.log("foo");
+        try {
+            (async function() {
+                return "bar";
+            })().then(console.log);
+        } finally {
+            console.log("baz");
+        }
+        console.log("moo");
+    }
+    expect_stdout: [
+        "foo",
+        "baz",
+        "moo",
+        "bar",
+    ]
+    node_version: ">=8"
+}
+
+issue_4974: {
+    options = {
+        awaits: true,
+        side_effects: true,
+    }
+    input: {
+        (async function f() {
+            return 42 in f();
+        })();
+        console.log("PASS");
+    }
+    expect: {
+        (async function f() {
+            return 42 in f();
+        })();
+        console.log("PASS");
+    }
+    expect_stdout: true
+    node_version: ">=8"
+}
+
+issue_4975: {
+    options = {
+        awaits: true,
+        side_effects: true,
+    }
+    input: {
+        (async function f(a) {
+            try {
+                if (a) console.log(typeof f());
+            } catch (e) {}
+        })(42);
+    }
+    expect: {
+        (async function f(a) {
+            try {
+                if (a) console.log(typeof f());
+            } catch (e) {}
+        })(42);
+    }
+    expect_stdout: "object"
+    node_version: ">=8"
+}
+
+issue_4987: {
+    options = {
+        awaits: true,
+        side_effects: true,
+    }
+    input: {
+        (async function() {
+            try {
+                await 42;
+            } finally {
+                console.log("foo");
+            }
+        })();
+        console.log("bar");
+    }
+    expect: {
+        (async function() {
+            try {
+                await 0;
+            } finally {
+                console.log("foo");
+            }
+        })();
+        console.log("bar");
+    }
+    expect_stdout: [
+        "bar",
+        "foo",
+    ]
+    node_version: ">=8"
+}

test/compress/bigint.js

@@ -60,3 +60,33 @@ issue_4590: {
     expect_stdout: "PASS"
     node_version: ">=10"
 }
+
+issue_4801: {
+    options = {
+        booleans: true,
+        collapse_vars: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        try {
+            (function(a) {
+                A = 42;
+                a || A;
+            })(!(0 == 42 >> 0o644n));
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect: {
+        try {
+            (function(a) {
+                0 != (A = 42) >> 0o644n || A;
+            })();
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect_stdout: "PASS"
+    node_version: ">=10"
+}

test/compress/collapse_vars.js

@@ -958,8 +958,7 @@ collapse_vars_misc: {
     }
     expect: {
         function f0(o, a, h) {
-            var b = 3 - a;
+            return o.run(3 - a)[7] = h;
-            return o.run(b)[7] = h;
         }
         function f1(x) { return 5 - x }
         function f2(x) { return foo() / (5 - x) }
@@ -2265,6 +2264,7 @@ var_defs: {
         properties: true,
         sequences: true,
         side_effects: true,
+        unsafe: true,
         unused: true,
     }
     input: {
@@ -2276,8 +2276,8 @@ var_defs: {
     }
     expect: {
         var f1 = function(x, y) {
-            var r = x + y, z = r * r - r, b = 7;
+            var r = x + y;
-            console.log(z + b);
+            console.log(r * r - r + 7);
         };
         f1("1", 0);
     }
@@ -2487,6 +2487,7 @@ issue_1858: {
     options = {
         collapse_vars: true,
         pure_getters: true,
+        reduce_vars: true,
         unused: true,
     }
     input: {
@@ -2869,7 +2870,7 @@ lvalues_def: {
     expect_stdout: true
 }
 
-compound_assignment: {
+compound_assignment_1: {
     options = {
         collapse_vars: true,
     }
@@ -2888,9 +2889,27 @@ compound_assignment: {
     expect_stdout: "4"
 }
 
+compound_assignment_2: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        var a;
+        a = 1;
+        for (a += a + 2; console.log(a););
+    }
+    expect: {
+        var a;
+        a = 1;
+        for (a += a + 2; console.log(a););
+    }
+    expect_stdout: "4"
+}
+
 issue_2187_1: {
     options = {
         collapse_vars: true,
+        reduce_vars: true,
         unused: true,
     }
     input: {
@@ -2907,8 +2926,7 @@ issue_2187_1: {
         var a = 1;
         !function(foo) {
             foo();
-            var a = 2;
+            console.log(2);
-            console.log(a);
         }(function() {
             console.log(a);
         });
@@ -4256,6 +4274,7 @@ issue_2436_14: {
     options = {
         collapse_vars: true,
         reduce_vars: true,
+        unsafe: true,
         unused: true,
     }
     input: {
@@ -4709,7 +4728,7 @@ cascade_statement: {
         }
         function f3(a, b) {
             for (; a < b; a++)
-                if ((c = a) && b)
+                if (c = a, a && b)
                     var c = c = b(a);
         }
     }
@@ -4746,6 +4765,7 @@ unsafe_builtin: {
     options = {
         collapse_vars: true,
         pure_getters: "strict",
+        reduce_vars: true,
         unsafe: true,
         unused: true,
     }
@@ -6950,6 +6970,7 @@ sequence_in_iife_2: {
         inline: true,
         passes: 2,
         side_effects: true,
+        unsafe: true,
         unused: true,
     }
     input: {
@@ -6961,8 +6982,7 @@ sequence_in_iife_2: {
     }
     expect: {
         var a = "foo", b = 42;
-        b = a;
+        console.log(b = a, b);
-        console.log(a, b);
     }
     expect_stdout: "foo foo"
 }
@@ -6974,6 +6994,7 @@ sequence_in_iife_3: {
         passes: 2,
         side_effects: true,
         toplevel: true,
+        unsafe: true,
         unused: true,
     }
     input: {
@@ -7078,6 +7099,7 @@ setter_side_effect: {
 substitution_assign: {
     options = {
         collapse_vars: true,
+        unsafe: true,
     }
     input: {
         function f1(a, b) {
@@ -7098,8 +7120,7 @@ substitution_assign: {
     }
     expect: {
         function f1(a, b) {
-            f1 = a;
+            console.log(f1 = a, a);
-            console.log(a, a);
         }
         function f2(a, b) {
             a = 1 + (b = a);
@@ -7903,6 +7924,7 @@ issue_3744: {
 assign_value_def: {
     options = {
         collapse_vars: true,
+        reduce_vars: true,
         unused: true,
     }
     input: {
@@ -7943,6 +7965,7 @@ join_vars_value_def: {
     options = {
         collapse_vars: true,
         join_vars: true,
+        reduce_vars: true,
         unused: true,
     }
     input: {
@@ -7982,6 +8005,7 @@ join_vars_value_def: {
 var_value_def: {
     options = {
         collapse_vars: true,
+        reduce_vars: true,
         unused: true,
     }
     input: {
@@ -8019,6 +8043,7 @@ var_value_def: {
 mangleable_var: {
     options = {
         collapse_vars: true,
+        reduce_vars: true,
         unused: true,
     }
     input: {
@@ -8050,6 +8075,69 @@ mangleable_var: {
     expect_stdout: "PASS"
 }
 
+mangleable_assignment_1: {
+    options = {
+        collapse_vars: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        var o = {
+            p: function() {
+                return 6;
+            },
+        };
+        (function() {
+            var a, b = a = o.p();
+            console.log(a * (b / a + b));
+        })();
+    }
+    expect: {
+        var o = {
+            p: function() {
+                return 6;
+            },
+        };
+        (function() {
+            var a;
+            a = o.p();
+            console.log(a * (a / a + a));
+        })();
+    }
+    expect_stdout: "42"
+}
+
+mangleable_assignment_2: {
+    options = {
+        collapse_vars: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        var o = {
+            p: function() {
+                return 6;
+            },
+        };
+        (function(a, b) {
+            b = a = o.p();
+            console.log(a * (b / a + b));
+        })();
+    }
+    expect: {
+        var o = {
+            p: function() {
+                return 6;
+            },
+        };
+        (function(a, b) {
+            a = o.p();
+            console.log(a * (a / a + a));
+        })();
+    }
+    expect_stdout: "42"
+}
+
 issue_3884_1: {
     options = {
         collapse_vars: true,
@@ -8485,7 +8573,7 @@ issue_4047_1: {
     expect: {
         var b = 1;
         var a;
-        console.log((a = --b + ((a = 0) !== typeof A), +void ((a >>= 0) && console.log("PASS"))));
+        console.log((a = --b + (0 !== typeof A), +void ((a >>= 0) && console.log("PASS"))));
     }
     expect_stdout: [
         "PASS",
@@ -8756,3 +8844,571 @@ issue_4586_2: {
     }
     expect_stdout: "PASS"
 }
+
+issue_4732_1: {
+    options = {
+        booleans: true,
+        collapse_vars: true,
+        evaluate: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        var a = 0;
+        (function(b) {
+            var b = a++;
+            var c = b ? b && console.log("PASS") : 0;
+        })(a++);
+    }
+    expect: {
+        var a = 0;
+        (function(b) {
+            (b = a++) && (b && console.log("PASS"));
+        })(a++);
+    }
+    expect_stdout: "PASS"
+}
+
+issue_4732_2: {
+    options = {
+        collapse_vars: true,
+        conditionals: true,
+        evaluate: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        var a = 0;
+        (function(b) {
+            var b = a++;
+            var c = b ? b && console.log("PASS") : 0;
+        })(a++);
+    }
+    expect: {
+        var a = 0;
+        (function(b) {
+            (b = a++) && b && console.log("PASS");
+        })(a++);
+    }
+    expect_stdout: "PASS"
+}
+
+dot_in_try: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        var o, a = 6, b = 7, c;
+        try {
+            c = a * b;
+            o.p(c);
+        } catch (e) {
+            console.log(c);
+        }
+    }
+    expect: {
+        var o, a = 6, b = 7, c;
+        try {
+            c = a * b;
+            o.p(c);
+        } catch (e) {
+            console.log(c);
+        }
+    }
+    expect_stdout: "42"
+}
+
+dot_non_local: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        var o, a = 6, b = 7, c;
+        function f() {
+            c = a * b;
+            o.p(c);
+        }
+        try {
+            f();
+        } catch (e) {
+            console.log(c);
+        }
+    }
+    expect: {
+        var o, a = 6, b = 7, c;
+        function f() {
+            c = a * b;
+            o.p(c);
+        }
+        try {
+            f();
+        } catch (e) {
+            console.log(c);
+        }
+    }
+    expect_stdout: "42"
+}
+
+issue_4806: {
+    options = {
+        collapse_vars: true,
+        reduce_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var a, o = {
+            f: function() {
+                console.log(this === o ? "FAIL" : "PASS");
+            },
+        };
+        (a = 42, o.f)(42);
+    }
+    expect: {
+        var a, o = {
+            f: function() {
+                console.log(this === o ? "FAIL" : "PASS");
+            },
+        };
+        (0, o.f)(a = 42);
+    }
+    expect_stdout: "PASS"
+}
+
+issue_4852: {
+    options = {
+        collapse_vars: true,
+        unsafe: true,
+    }
+    input: {
+        var a = "PASS";
+        (function(b) {
+            switch (b = a) {
+              case 42:
+                try {
+                    console;
+                } catch (b) {
+                    b.p;
+                }
+              case console.log(b):
+            }
+        })("FAIL");
+    }
+    expect: {
+        var a = "PASS";
+        (function(b) {
+            switch (a) {
+              case 42:
+                try {
+                    console;
+                } catch (b) {
+                    b.p;
+                }
+              case console.log(a):
+            }
+        })("FAIL");
+    }
+    expect_stdout: "PASS"
+}
+
+issue_4865: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        var NaN;
+        var a = NaN = "PASS";
+        console.log(a, NaN);
+    }
+    expect: {
+        var NaN;
+        var a = NaN = "PASS";
+        console.log(a, NaN);
+    }
+    expect_stdout: true
+}
+
+issue_4868: {
+    options = {
+        collapse_vars: true,
+        unused: true,
+    }
+    input: {
+        var a;
+        (function(b) {
+            console.log(b[0]);
+        })(a = [ "PASS" ], a = [ "FAIL" ]);
+    }
+    expect: {
+        var a;
+        (function(b) {
+            console.log(b[0]);
+        })(a = [ "PASS" ], a = [ "FAIL" ]);
+    }
+    expect_stdout: "PASS"
+}
+
+issue_4874: {
+    options = {
+        collapse_vars: true,
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a;
+        a = null;
+        (function(b) {
+            for (var c in b = b && b[console.log("PASS")])
+                console;
+        })(a = 42);
+    }
+    expect: {
+        var a;
+        null;
+        (function(b) {
+            for (var c in a && a[console.log("PASS")])
+                console;
+        })(a = 42);
+    }
+    expect_stdout: "PASS"
+}
+
+issue_4891: {
+    options = {
+        collapse_vars: true,
+        reduce_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var a = 0, b;
+        a++;
+        console.log(b = a, b);
+        b--;
+        a.a += 0;
+        console.log(b);
+    }
+    expect: {
+        var a = 0, b;
+        a++;
+        console.log(a, b = a);
+        b--;
+        a.a += 0;
+        console.log(b);
+    }
+    expect_stdout: [
+        "1 1",
+        "0",
+    ]
+}
+
+issue_4895: {
+    options = {
+        collapse_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var a, b;
+        (function f() {
+            a = 42;
+        })();
+        console.log((b = a) || b, b += 0);
+    }
+    expect: {
+        var a, b;
+        (function f() {
+            a = 42;
+        })();
+        console.log((b = a) || b, b += 0);
+    }
+    expect_stdout: "42 42"
+}
+
+issue_4908: {
+    options = {
+        collapse_vars: true,
+        join_vars: true,
+        reduce_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var a = 0;
+        var b;
+        console || a++;
+        var c = d = a, d = [ c && c, d += 42 ];
+        console.log(d[1]);
+    }
+    expect: {
+        var a = 0, b;
+        console || a++;
+        var c = a, d = [ (d = a) && d, d += 42 ];
+        console.log(d[1]);
+    }
+    expect_stdout: "42"
+}
+
+issue_4910: {
+    options = {
+        collapse_vars: true,
+        reduce_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var a = "foo", b;
+        var c = b = a;
+        1 && c[a = "bar"];
+        console.log(a, b);
+    }
+    expect: {
+        var a = "foo", b;
+        var c = b = a;
+        1 && b[a = "bar"];
+        console.log(a, b);
+    }
+    expect_stdout: "bar foo"
+}
+
+issue_4914: {
+    options = {
+        collapse_vars: true,
+        pure_getters: "strict",
+    }
+    input: {
+        console.log(typeof function f() {
+            f.__proto__ = 42;
+            return f.__proto__;
+        }());
+    }
+    expect: {
+        console.log(typeof function f() {
+            f.__proto__ = 42;
+            return f.__proto__;
+        }());
+    }
+    expect_stdout: "function"
+}
+
+issue_4918: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        var a = "FAIL";
+        ({
+            get 42() {
+                console.log(a);
+            }
+        }[a = "PASS", 42] += "PASS");
+    }
+    expect: {
+        var a = "FAIL";
+        ({
+            get 42() {
+                console.log(a);
+            }
+        }[a = "PASS", 42] += "PASS");
+    }
+    expect_stdout: "PASS"
+}
+
+issue_4920_1: {
+    options = {
+        collapse_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var a = "PASS", b;
+        ({
+            get PASS() {
+                a = "FAIL";
+            },
+        })[b = a];
+        console.log(b);
+    }
+    expect: {
+        var a = "PASS", b;
+        ({
+            get PASS() {
+                a = "FAIL";
+            },
+        })[b = a];
+        console.log(b);
+    }
+    expect_stdout: "PASS"
+}
+
+issue_4920_2: {
+    options = {
+        collapse_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var o = {
+            get PASS() {
+                a = "FAIL";
+            },
+        };
+        var a = "PASS", b;
+        o[b = a];
+        console.log(b);
+    }
+    expect: {
+        var o = {
+            get PASS() {
+                a = "FAIL";
+            },
+        };
+        var a = "PASS", b;
+        o[b = a];
+        console.log(b);
+    }
+    expect_stdout: "PASS"
+}
+
+issue_4920_3: {
+    options = {
+        collapse_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var log = console.log;
+        var o = {
+            get PASS() {
+                a = "FAIL";
+            },
+        };
+        var a = "PASS", b;
+        o[b = a];
+        log(b);
+    }
+    expect: {
+        var log = console.log;
+        var o = {
+            get PASS() {
+                a = "FAIL";
+            },
+        };
+        var a = "PASS", b;
+        o[b = a];
+        log(b);
+    }
+    expect_stdout: "PASS"
+}
+
+issue_4935: {
+    options = {
+        collapse_vars: true,
+        reduce_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var a = 1;
+        var b;
+        var c = b = a;
+        console || c(a++);
+        --b;
+        console.log(a, b);
+    }
+    expect: {
+        var a = 1;
+        var b;
+        var c = b = a;
+        console || a(a++);
+        --b;
+        console.log(a, b);
+    }
+    expect_stdout: "1 0"
+}
+
+inline_throw: {
+    options = {
+        collapse_vars: true,
+        inline: true,
+        keep_fargs: false,
+        unused: true,
+    }
+    input: {
+        try {
+            (function() {
+                return function(a) {
+                    return function(b) {
+                        throw b;
+                    }(a);
+                };
+            })()("PASS");
+        } catch (e) {
+            console.log(e);
+        }
+    }
+    expect: {
+        try {
+            (function(a) {
+                return function() {
+                    throw a;
+                }();
+            })("PASS");
+        } catch (e) {
+            console.log(e);
+        }
+    }
+    expect_stdout: "PASS"
+}
+
+issue_4977_1: {
+    options = {
+        collapse_vars: true,
+        unsafe: true,
+    }
+    input: {
+        var a = "FAIL";
+        var o = {
+            get p() {
+                return a;
+            }
+        };
+        a = "PASS";
+        console.log(o.p, a);
+    }
+    expect: {
+        var a = "FAIL";
+        var o = {
+            get p() {
+                return a;
+            }
+        };
+        a = "PASS";
+        console.log(o.p, a);
+    }
+    expect_stdout: "PASS PASS"
+}
+
+issue_4977_2: {
+    options = {
+        collapse_vars: true,
+        reduce_vars: true,
+        unsafe: true,
+    }
+    input: {
+        var a, o = {
+            get p() {
+                return a = "PASS";
+            },
+        };
+        if (console) {
+            var a = "FAIL";
+            console.log(o.p, a);
+        }
+    }
+    expect: {
+        var a, o = {
+            get p() {
+                return a = "PASS";
+            },
+        };
+        if (console) {
+            var a = "FAIL";
+            console.log(o.p, a);
+        }
+    }
+    expect_stdout: "PASS PASS"
+}

test/compress/const.js

@@ -1498,3 +1498,197 @@ issue_4691: {
     }
     expect_stdout: "PASS"
 }
+
+issue_4848: {
+    options = {
+        if_return: true,
+    }
+    input: {
+        function f(a) {
+            a(function() {
+                console.log(b);
+            });
+            if (!console)
+                return;
+            const b = "PASS";
+        }
+        var g;
+        f(function(h) {
+            g = h;
+        });
+        g();
+    }
+    expect: {
+        function f(a) {
+            a(function() {
+                console.log(b);
+            });
+            if (!console)
+                return;
+            const b = "PASS";
+        }
+        var g;
+        f(function(h) {
+            g = h;
+        });
+        g();
+    }
+    expect_stdout: "PASS"
+}
+
+issue_4954_1: {
+    rename = true
+    input: {
+        "use strict";
+        (function() {
+            {
+                const a = "foo";
+                console.log(a);
+            }
+            {
+                const a = "bar";
+                console.log(a);
+            }
+        })();
+    }
+    expect: {
+        "use strict";
+        (function() {
+            {
+                const a = "foo";
+                console.log(a);
+            }
+            {
+                const b = "bar";
+                console.log(b);
+            }
+        })();
+    }
+    expect_stdout: [
+        "foo",
+        "bar",
+    ]
+    node_version: ">=4"
+}
+
+issue_4954_2: {
+    mangle = {}
+    input: {
+        "use strict";
+        const a = null;
+        (function(b) {
+            for (const a in null);
+            for (const a in b)
+                console.log("PASS");
+        })([ null ]);
+    }
+    expect: {
+        "use strict";
+        const a = null;
+        (function(o) {
+            for (const n in null);
+            for (const n in o)
+                console.log("PASS");
+        })([ null ]);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
+issue_4960: {
+    mangle = {}
+    input: {
+        "use strict";
+        var a;
+        (function() {
+            {
+                const a = console.log("PASS");
+            }
+            try {} catch (e) {
+                const a = console.log("FAIL");
+            }
+        })();
+    }
+    expect: {
+        "use strict";
+        var a;
+        (function() {
+            {
+                const o = console.log("PASS");
+            }
+            try {} catch (o) {
+                const c = console.log("FAIL");
+            }
+        })();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
+issue_4965_1: {
+    mangle = {}
+    input: {
+        "use strict";
+        try {
+            c;
+        } catch (a) {
+            {
+                const a = 1;
+            }
+            {
+                const a = console.log(typeof c);
+            }
+        }
+    }
+    expect: {
+        "use strict";
+        try {
+            c;
+        } catch (t) {
+            {
+                const c = 1;
+            }
+            {
+                const t = console.log(typeof c);
+            }
+        }
+    }
+    expect_stdout: "undefined"
+    node_version: ">=4"
+}
+
+issue_4965_2: {
+    mangle = {}
+    input: {
+        "use strict";
+        try {
+            throw 1;
+        } catch (e) {
+            try {
+                {
+                    const e = 2;
+                }
+            } finally {
+                const e = 3;
+                console.log(typeof t);
+            }
+        }
+    }
+    expect: {
+        "use strict";
+        try {
+            throw 1;
+        } catch (o) {
+            try {
+                {
+                    const t = 2;
+                }
+            } finally {
+                const o = 3;
+                console.log(typeof t);
+            }
+        }
+    }
+    expect_stdout: "undefined"
+    node_version: ">=4"
+}

test/compress/default-values.js

@@ -598,6 +598,7 @@ unused_var_1: {
 
 unused_var_2: {
     options = {
+        pure_getters: "strict",
         toplevel: true,
         unused: true,
     }
@@ -609,11 +610,7 @@ unused_var_2: {
         };
     }
     expect: {
-        var {
+        console.log("PASS");
-            p: [] = [ console.log("FAIL") ],
-        } = {
-            p: [ console.log("PASS") ],
-        };
     }
     expect_stdout: "PASS"
     node_version: ">=6"
@@ -1661,3 +1658,71 @@ issue_4588_2_evaluate: {
     expect_stdout: "1"
     node_version: ">=6"
 }
+
+issue_4817: {
+    options = {
+        ie8: true,
+        inline: true,
+        unused: true,
+    }
+    input: {
+        (function f(a = console.log(typeof f)) {
+            return 42;
+        })();
+    }
+    expect: {
+        (function f(a = console.log(typeof f)) {
+            return 42;
+        })();
+    }
+    expect_stdout: "function"
+    node_version: ">=6"
+}
+
+issue_4854: {
+    options = {
+        collapse_vars: true,
+        inline: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        console.log(function(a) {
+            (function(b = a = "foo") {
+                [] = "foo";
+            })();
+            a;
+        }());
+    }
+    expect: {
+        console.log(void ([] = "foo"));
+    }
+    expect_stdout: "undefined"
+    node_version: ">=6"
+}
+
+issue_4916: {
+    options = {
+        collapse_vars: true,
+        pure_getters: "strict",
+        reduce_vars: true,
+    }
+    input: {
+        var log = console.log;
+        (function(b = "foo") {
+            b.value = "FAIL";
+            b;
+            log(b.value);
+        })();
+    }
+    expect: {
+        var log = console.log;
+        (function(b = "foo") {
+            b.value = "FAIL";
+            b;
+            log(b.value);
+        })();
+    }
+    expect_stdout: "undefined"
+    node_version: ">=6"
+}

test/compress/destructured.js

@@ -1010,6 +1010,42 @@ collapse_vars_8: {
     node_version: ">=6"
 }
 
+collapse_vars_9: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        console.log(function(a) {
+            try {
+                var b = function([ c ]) {
+                    if (c)
+                        return "FAIL 1";
+                }();
+                a = "FAIL 2";
+                return b;
+            } catch (e) {
+                return a;
+            }
+        }("PASS"));
+    }
+    expect: {
+        console.log(function(a) {
+            try {
+                var b = function([ c ]) {
+                    if (c)
+                        return "FAIL 1";
+                }();
+                a = "FAIL 2";
+                return b;
+            } catch (e) {
+                return a;
+            }
+        }("PASS"));
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
 conditionals: {
     options = {
         conditionals: true,

test/compress/drop-unused.js

@@ -2371,6 +2371,7 @@ function_parameter_ie8: {
 issue_3664: {
     options = {
         pure_getters: "strict",
+        side_effects: true,
         unused: true,
     }
     input: {
@@ -2381,7 +2382,7 @@ issue_3664: {
     }
     expect: {
         console.log(function() {
-            var b = ([ b && console.log("FAIL") ].p = 0, 0);
+            var a, b = (a = (a = [ b && console.log("FAIL") ]).p = 0, 0);
             return "PASS";
         }());
     }
@@ -2391,6 +2392,7 @@ issue_3664: {
 issue_3673: {
     options = {
         pure_getters: "strict",
+        sequences: true,
         side_effects: true,
         toplevel: true,
         unused: true,
@@ -2401,8 +2403,6 @@ issue_3673: {
         console.log("PASS");
     }
     expect: {
-        var a;
-        (a = [ a ]).p = 42;
         console.log("PASS");
     }
     expect_stdout: "PASS"
@@ -3080,11 +3080,9 @@ issue_4235: {
         })();
     }
     expect: {
-        (function() {
+        void function() {
-            f = console.log(f),
+            var f = console.log(f);
-            void 0;
+        }();
-            var f;
-        })();
     }
     expect_stdout: "undefined"
 }
@@ -3274,3 +3272,199 @@ issue_4662: {
     }
     expect_stdout: "1 1"
 }
+
+issue_4806_1: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        O = {
+            f: function() {
+                console.log(this === O ? "FAIL" : "PASS");
+            },
+        };
+        var a;
+        (a = 42, O.f)();
+        a;
+    }
+    expect: {
+        O = {
+            f: function() {
+                console.log(this === O ? "FAIL" : "PASS");
+            },
+        };
+        (0, O.f)();
+        42;
+    }
+    expect_stdout: "PASS"
+}
+
+issue_4806_2: {
+    options = {
+        sequences: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        O = {
+            f: function() {
+                console.log(this === O ? "FAIL" : "PASS");
+            },
+        };
+        var a;
+        (a = 42, O.f)();
+        a;
+    }
+    expect: {
+        O = {
+            f: function() {
+                console.log(this === O ? "FAIL" : "PASS");
+            },
+        },
+        (0, O.f)();
+    }
+    expect_stdout: "PASS"
+}
+
+issue_4806_3: {
+    options = {
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        O = {
+            f: function() {
+                console.log(this === O ? "FAIL" : "PASS");
+            },
+        };
+        var a;
+        (a = 42, O.f)();
+        a;
+    }
+    expect: {
+        O = {
+            f: function() {
+                console.log(this === O ? "FAIL" : "PASS");
+            },
+        };
+        (0, O.f)();
+    }
+    expect_stdout: "PASS"
+}
+
+issue_4834: {
+    options = {
+        inline: true,
+        keep_fargs: false,
+        pure_getters: "strict",
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        try {
+            new function(a, b) {
+                b;
+                b.p;
+            }(42);
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect: {
+        try {
+            void b.p;
+        } catch (e) {
+            console.log("PASS");
+        }
+        var b;
+    }
+    expect_stdout: "PASS"
+}
+
+issue_4912_1: {
+    options = {
+        pure_getters: "strict",
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = A = function() {};
+        A;
+        a.prototype = {
+            f: function() {
+                console.log("PASS");
+            },
+        };
+        new A().f();
+    }
+    expect: {
+        var a = A = function() {};
+        A;
+        a.prototype = {
+            f: function() {
+                console.log("PASS");
+            },
+        };
+        new A().f();
+    }
+    expect_stdout: "PASS"
+}
+
+issue_4912_2: {
+    options = {
+        pure_getters: "strict",
+        unused: true,
+    }
+    input: {
+        console.log(function() {
+            var g, f = function() {};
+            f.p = {};
+            (g = f.p.q = function() {}).r = "PASS";
+            return f;
+        }().p.q.r);
+    }
+    expect: {
+        console.log(function() {
+            var g, f = function() {};
+            f.p = {};
+            (f.p.q = function() {}).r = "PASS";
+            return f;
+        }().p.q.r);
+    }
+    expect_stdout: "PASS"
+}
+
+issue_4912_3: {
+    options = {
+        pure_getters: "strict",
+        reduce_vars: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        console.log(function(f, g) {
+            f = function() {};
+            f.p = {};
+            g = f.p.q = function() {};
+            g.r = "PASS";
+            return f;
+        }().p.q.r);
+    }
+    expect: {
+        console.log(function(f, g) {
+            f = function() {};
+            f.p = {};
+            g = f.p.q = function() {};
+            g.r = "PASS";
+            return f;
+        }().p.q.r);
+    }
+    expect_stdout: "PASS"
+}

test/compress/evaluate.js

@@ -847,6 +847,8 @@ unsafe_charAt_noop: {
         unsafe: true,
     }
     input: {
+        s = "foo";
+        x = 42;
         console.log(
             s.charAt(0),
             "string".charAt(x),
@@ -854,12 +856,15 @@ unsafe_charAt_noop: {
         );
     }
     expect: {
+        s = "foo";
+        x = 42;
         console.log(
-            s[0],
+            s[0] || "",
-            "string"[0 | x],
+            "string"[0 | x] || "",
-            (typeof x)[0]
+            (typeof x)[0] || ""
         );
     }
+    expect_stdout: "f  n"
 }
 
 issue_1649: {
@@ -3176,3 +3181,23 @@ issue_4552: {
     }
     expect_stdout: "NaN"
 }
+
+issue_4886: {
+    options = {
+        evaluate: true,
+        unsafe: true,
+    }
+    input: {
+        console.log("length" in {
+            __proto__: function() {},
+            length: void 0,
+        });
+    }
+    expect: {
+        console.log("length" in {
+            __proto__: function() {},
+            length: void 0,
+        });
+    }
+    expect_stdout: "true"
+}

test/compress/exponentiation.js

@@ -43,6 +43,28 @@ await: {
     node_version: ">=8"
 }
 
+assignment_1: {
+    input: {
+        var a = 2;
+        a **= 5;
+        console.log(a);
+    }
+    expect_exact: "var a=2;a**=5;console.log(a);"
+    expect_stdout: "32"
+    node_version: ">=8"
+}
+
+assignment_2: {
+    input: {
+        var a = 8n;
+        a **= a;
+        console.log(a);
+    }
+    expect_exact: "var a=8n;a**=a;console.log(a);"
+    expect_stdout: "16777216n"
+    node_version: ">=10"
+}
+
 evaluate: {
     options = {
         evaluate: true,
@@ -77,10 +99,49 @@ issue_4664: {
     expect: {
         (function f() {
             new function(a) {
-                console.log(typeof f, 2 ** 30, typeof this);
+                console.log(typeof f, 1073741824, typeof this);
-            }(0, A = 0);
+            }(A = 0);
         })();
     }
     expect_stdout: "function 1073741824 object"
     node_version: ">=8"
 }
+
+issue_4715: {
+    options = {
+        evaluate: true,
+    }
+    input: {
+        A = 1;
+        console.log((-0) ** A + 0);
+        console.log((-0) ** A - 0);
+        console.log((-0) ** A * 1);
+        console.log((-0) ** A / 1);
+        console.log(Math.pow(-0, A) + 0);
+        console.log(Math.pow(-0, A) - 0);
+        console.log(Math.pow(-0, A) * 1);
+        console.log(Math.pow(-0, A) / 1);
+    }
+    expect: {
+        A = 1;
+        console.log((-0) ** A + 0);
+        console.log((-0) ** A);
+        console.log((-0) ** A * 1);
+        console.log((-0) ** A);
+        console.log(Math.pow(-0, A) + 0);
+        console.log(+Math.pow(-0, A));
+        console.log(+Math.pow(-0, A));
+        console.log(+Math.pow(-0, A));
+    }
+    expect_stdout: [
+        "0",
+        "-0",
+        "-0",
+        "-0",
+        "0",
+        "-0",
+        "-0",
+        "-0",
+    ]
+    node_version: ">=8"
+}

test/compress/exports.js

@@ -3,7 +3,7 @@ refs: {
         export {};
         export { a, b as B, c as case, d as default };
     }
-    expect_exact: "export{};export{a as a,b as B,c as case,d as default};"
+    expect_exact: "export{};export{a,b as B,c as case,d as default};"
 }
 
 var_defs: {
@@ -12,7 +12,7 @@ var_defs: {
         export let b = 2, c = 3;
         export var { d, e: [] } = f;
     }
-    expect_exact: "export const a=1;export let b=2,c=3;export var{d:d,e:[]}=f;"
+    expect_exact: "export const a=1;export let b=2,c=3;export var{d,e:[]}=f;"
 }
 
 defuns: {
@@ -35,7 +35,7 @@ defaults: {
         export default function*(a, b) {};
         export default async function f({ c }, ...[ d ]) {};
     }
-    expect_exact: "export default 42;export default async;export default(x,y)=>x*x;export default class{}export default function*(a,b){}export default async function f({c:c},...[d]){}"
+    expect_exact: "export default 42;export default async;export default(x,y)=>x*x;export default class{}export default function*(a,b){}export default async function f({c},...[d]){}"
 }
 
 defaults_parentheses_1: {
@@ -91,6 +91,13 @@ defaults_parentheses_6: {
     expect_exact: 'export default(function(){while(!console);})()?"FAIL":"PASS";'
 }
 
+defaults_regexp: {
+    input: {
+        export default /foo/;
+    }
+    expect_exact: "export default/foo/;"
+}
+
 foreign: {
     input: {
         export * from "foo";
@@ -203,7 +210,23 @@ mangle_rename: {
     }
 }
 
-hoist_exports: {
+hoist_exports_1: {
+    options = {
+        hoist_exports: true,
+    }
+    input: {
+        export { a };
+        export var b;
+        export function f() {}
+    }
+    expect: {
+        var b;
+        function f() {}
+        export { a, b, f };
+    }
+}
+
+hoist_exports_2: {
     options = {
         evaluate: true,
         hoist_exports: true,
@@ -226,15 +249,15 @@ hoist_exports: {
         }
     }
     expect: {
-        let f, { foo: o } = 42;
+        let e, { foo: a } = 42;
-        function c(t, { [f]: a }) {
+        function f(t, { [e]: o }) {
-            t(a, c);
+            t(o, f);
         }
         export default 42;
-        export default async function e(t, ...{ [o]: a }) {
+        export default async function n(t, ...{ [a]: o }) {
-            (await t)(e, a);
+            (await t)(n, o);
         };
-        export { f as bbb, o as ccc, c as fff };
+        export { e as bbb, a as ccc, f as fff };
     }
 }
 
@@ -382,3 +405,94 @@ single_use_class_default: {
         A.prototype.p = "PASS";
     }
 }
+
+hoist_funs: {
+    options = {
+        hoist_funs: true,
+    }
+    input: {
+        export function f() {}
+        export default async function* g() {}
+    }
+    expect_exact: "export function f(){}export default async function*g(){}"
+}
+
+issue_4742_join_vars_1: {
+    options = {
+        join_vars: true,
+    }
+    input: {
+        var a = 42;
+        export var a;
+    }
+    expect: {
+        var a = 42;
+        export var a;
+    }
+}
+
+issue_4742_join_vars_2: {
+    options = {
+        join_vars: true,
+    }
+    input: {
+        export var a = "foo";
+        var b;
+        b = "bar";
+    }
+    expect: {
+        export var a = "foo";
+        var b, b = "bar";
+    }
+}
+
+issue_4742_unused_1: {
+    options = {
+        unused: true,
+    }
+    input: {
+        var a = 42;
+        export var a;
+    }
+    expect: {
+        var a = 42;
+        export var a;
+    }
+}
+
+issue_4742_unused_2: {
+    options = {
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        export var a = "foo";
+        var a = "bar";
+    }
+    expect: {
+        export var a = "foo";
+        a = "bar";
+    }
+}
+
+issue_4761: {
+    input: {
+        export default "function" == 42;
+    }
+    expect_exact: 'export default"function"==42;'
+}
+
+issue_4766: {
+    options = {
+        unused: true,
+    }
+    input: {
+        var a = "foo";
+        export var a = "bar";
+    }
+    expect: {
+        var a = "foo";
+        export var a = "bar";
+    }
+}

test/compress/functions.js

@@ -2492,14 +2492,14 @@ issue_3297_3: {
     input: {
         function function1(session) {
             var public = {
-                processBulk: processBulk
+                processBulk: processBulk,
             };
             return public;
             function processBulk(bulk) {
                 var subparam1 = session();
                 function processOne(param1) {
                     var param2 = {
-                        subparam1: subparam1
+                        subparam1: subparam1,
                     };
                     doProcessOne({
                         param1: param1,
@@ -2525,18 +2525,18 @@ issue_3297_3: {
             return {
                 processBulk: function n(o) {
                     var r, t, u = c();
-                    o && 0 < o.length && (r = {
+                    o && 0 < o.length && (r = o.shift(),
-                        param1: o.shift(),
-                        param2: {
-                            subparam1: u
-                        }
-                    },
                     t = function() {
                         n(o);
                     },
-                    console.log(JSON.stringify(r)),
+                    console.log(JSON.stringify({
+                        param1: r,
+                        param2: {
+                            subparam1: u,
+                        },
+                    })),
                     t());
-                }
+                },
             };
         }
         function1(function() {
@@ -2751,17 +2751,17 @@ functions: {
             function b() {
                 return !!b;
             }
-            var c = function(c) {
+            function c(c) {
                 return c;
-            };
+            }
             if (c(b(a()))) {
                 function d() {}
                 function e() {
                     return typeof e;
                 }
-                var f = function(f) {
+                function f(f) {
                     return f;
-                };
+                }
                 console.log(a(d()), b(e()), c(f(42)), typeof d, e(), typeof f);
             }
         }();
@@ -2808,9 +2808,9 @@ functions_use_strict: {
             function b() {
                 return !!b;
             }
-            var c = function(c) {
+            function c(c) {
                 return c;
-            };
+            }
             if (c(b(a()))) {
                 var d = function() {};
                 var e = function y() {
@@ -2826,6 +2826,30 @@ functions_use_strict: {
     expect_stdout: "a true 42 function function function"
 }
 
+functions_inner_var: {
+    options = {
+        functions: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = function() {
+            var a;
+            console.log(a, a);
+        };
+        a(a);
+    }
+    expect: {
+        function a() {
+            var a;
+            console.log(a, a);
+        }
+        a();
+    }
+    expect_stdout: "undefined undefined"
+}
+
 issue_2437: {
     options = {
         collapse_vars: true,
@@ -5212,7 +5236,7 @@ issue_4265: {
     expect: {
         function f() {
             return console, function() {
-                return console.log(a);
+                console.log(a);
                 var a;
             }(), 0;
         }
@@ -5698,3 +5722,509 @@ block_scope_4_compress: {
     }
     expect_stdout: "function"
 }
+
+issue_4725_1: {
+    options = {
+        inline: true,
+    }
+    input: {
+        var o = {
+            f() {
+                return function g() {
+                    return g;
+                }();
+            }
+        };
+        console.log(typeof o.f());
+    }
+    expect: {
+        var o = {
+            f() {
+                return function g() {
+                    return g;
+                }();
+            }
+        };
+        console.log(typeof o.f());
+    }
+    expect_stdout: "function"
+    node_version: ">=4"
+}
+
+issue_4725_2: {
+    options = {
+        inline: true,
+    }
+    input: {
+        var o = {
+            f() {
+                return function() {
+                    while (console.log("PASS"));
+                }();
+            }
+        };
+        o.f();
+    }
+    expect: {
+        var o = {
+            f() {
+                while (console.log("PASS"));
+            }
+        };
+        o.f();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
+new_target_1: {
+    input: {
+        new function f() {
+            console.log(new.target === f);
+        }();
+        console.log(function() {
+            return new.target;
+        }());
+    }
+    expect: {
+        new function f() {
+            console.log(new.target === f);
+        }();
+        console.log(function() {
+            return new.target;
+        }());
+    }
+    expect_stdout: [
+        "true",
+        "undefined",
+    ]
+    node_version: ">=6"
+}
+
+new_target_2: {
+    input: {
+        new function(a) {
+            if (!new.target)
+                console.log("FAIL");
+            else if (a)
+                console.log("PASS");
+            else
+                new new.target(new.target.length);
+        }();
+    }
+    expect: {
+        new function(a) {
+            if (!new.target)
+                console.log("FAIL");
+            else if (a)
+                console.log("PASS");
+            else
+                new new.target(new.target.length);
+        }();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+new_target_collapse_vars: {
+    options = {
+        collapse_vars: true,
+        unused: true,
+    }
+    input: {
+        new function(a) {
+            if (a)
+                console.log("PASS");
+            else
+                new new.target(new.target.length);
+        }(0);
+    }
+    expect: {
+        new function(a) {
+            if (a)
+                console.log("PASS");
+            else
+                new new.target(new.target.length);
+        }(0);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+new_target_delete: {
+    options = {
+        evaluate: true,
+    }
+    input: {
+        new function() {
+            console.log(delete new.target);
+        }();
+    }
+    expect: {
+        new function() {
+            console.log(delete new.target);
+        }();
+    }
+    expect_stdout: true
+    node_version: ">=6"
+}
+
+new_target_reduce_vars: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+    }
+    input: {
+        new function(a) {
+            if (a)
+                console.log("PASS");
+            else
+                new new.target(new.target.length);
+        }(0);
+    }
+    expect: {
+        new function(a) {
+            if (a)
+                console.log("PASS");
+            else
+                new new.target(new.target.length);
+        }(0);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_4753_1: {
+    options = {
+        inline: true,
+        toplevel: true,
+    }
+    input: {
+        for (var i in [ 1, 2 ])
+            (function() {
+                function f() {}
+                f && console.log(f.p ^= 42);
+            })();
+    }
+    expect: {
+        for (var i in [ 1, 2 ])
+            f = function() {},
+            void (f && console.log(f.p ^= 42));
+        var f;
+    }
+    expect_stdout: [
+        "42",
+        "42",
+    ]
+}
+
+issue_4753_2: {
+    options = {
+        inline: true,
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        do {
+            (function() {
+                var a = f();
+                function f() {
+                    return "PASS";
+                }
+                f;
+                function g() {
+                    console.log(a);
+                }
+                g();
+            })();
+        } while (0);
+    }
+    expect: {
+        do {
+            f = function() {
+                return "PASS";
+            },
+            a = void 0,
+            a = f(),
+            console.log(a);
+        } while (0);
+        var f, a;
+    }
+    expect_stdout: "PASS"
+}
+
+issue_4788: {
+    options = {
+        evaluate: true,
+        functions: true,
+        keep_fnames: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        function f() {
+            var a = function g() {
+                if (0) {
+                    var g = 42;
+                    f();
+                }
+                g || console.log("PASS");
+            };
+            a(a);
+        }
+        f();
+    }
+    expect: {
+        (function f() {
+            function a() {
+                if (0) {
+                    var g = 42;
+                    f();
+                }
+                g || console.log("PASS");
+            }
+            a();
+        })();
+    }
+    expect_stdout: "PASS"
+}
+
+issue_4823: {
+    options = {
+        functions: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        console.log(typeof function() {
+            {
+                function f() {}
+                var arguments = f();
+                function g() {}
+                var arguments = g;
+            }
+            return f && arguments;
+        }());
+    }
+    expect: {
+        console.log(typeof function() {
+            {
+                function f() {}
+                f();
+                var arguments = function() {};
+            }
+            return f && arguments;
+        }());
+    }
+    expect_stdout: "function"
+}
+
+drop_unused_self_reference: {
+    options = {
+        pure_getters: "strict",
+        reduce_vars: true,
+        sequences: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        function f() {}
+        (f.p = f).q = console.log("PASS");
+    }
+    expect: {
+        console.log("PASS");
+    }
+    expect_stdout: "PASS"
+}
+
+reduce_cross_reference_1: {
+    options = {
+        passes: 3,
+        pure_getters: "strict",
+        reduce_vars: true,
+        sequences: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        (function(a, b) {
+            a = b = function() {};
+            a.p = a;
+            b = a = function() {};
+            b.q = b;
+        })();
+    }
+    expect: {}
+    expect_stdout: true
+}
+
+reduce_cross_reference_1_toplevel: {
+    options = {
+        passes: 2,
+        pure_getters: "strict",
+        reduce_vars: true,
+        sequences: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = b = function() {};
+        a.p = a;
+        var b = a = function() {};
+        b.q = b;
+    }
+    expect: {}
+    expect_stdout: true
+}
+
+reduce_cross_reference_2: {
+    options = {
+        collapse_vars: true,
+        passes: 3,
+        pure_getters: "strict",
+        reduce_vars: true,
+        sequences: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        (function(a, b) {
+            a = b = function() {};
+            b.p = a;
+            b = a = function() {};
+            a.q = b;
+        })();
+    }
+    expect: {}
+    expect_stdout: true
+}
+
+reduce_cross_reference_2_toplevel: {
+    options = {
+        collapse_vars: true,
+        passes: 2,
+        pure_getters: "strict",
+        reduce_vars: true,
+        sequences: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = b = function() {};
+        b.p = a;
+        var b = a = function() {};
+        a.q = b;
+    }
+    expect: {}
+    expect_stdout: true
+}
+
+reduce_cross_reference_3: {
+    options = {
+        collapse_vars: true,
+        passes: 3,
+        pure_getters: "strict",
+        reduce_vars: true,
+        sequences: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        (function(a, b) {
+            a = b = function() {};
+            a.p = b;
+            b = a = function() {};
+            b.q = a;
+        })();
+    }
+    expect: {}
+    expect_stdout: true
+}
+
+reduce_cross_reference_3_toplevel: {
+    options = {
+        collapse_vars: true,
+        passes: 2,
+        pure_getters: "strict",
+        reduce_vars: true,
+        sequences: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = b = function() {};
+        a.p = b;
+        var b = a = function() {};
+        b.q = a;
+    }
+    expect: {}
+    expect_stdout: true
+}
+
+reduce_cross_reference_4: {
+    options = {
+        passes: 3,
+        pure_getters: "strict",
+        reduce_vars: true,
+        sequences: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        (function(a, b) {
+            a = b = function() {};
+            b.p = b;
+            b = a = function() {};
+            a.q = a;
+        })();
+    }
+    expect: {}
+    expect_stdout: true
+}
+
+reduce_cross_reference_4_toplevel: {
+    options = {
+        passes: 2,
+        pure_getters: "strict",
+        reduce_vars: true,
+        sequences: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = b = function() {};
+        b.p = b;
+        var b = a = function() {};
+        a.q = a;
+    }
+    expect: {}
+    expect_stdout: true
+}
+
+recursive_collapse: {
+    options = {
+        collapse_vars: true,
+        reduce_vars: true,
+    }
+    input: {
+        console.log(function f(a) {
+            var b = a && f();
+            return b;
+        }("FAIL") || "PASS");
+    }
+    expect: {
+        console.log(function f(a) {
+            var b;
+            return a && f();
+        }("FAIL") || "PASS");
+    }
+    expect_stdout: "PASS"
+}

test/compress/hoist_vars.js

@@ -152,7 +152,7 @@ issue_4487: {
     }
     expect: {
         function a() {
-            var a = console.log(typeof a);
+            var f = console.log(typeof f);
         }
         a();
     }
@@ -207,3 +207,192 @@ issue_4517: {
     }
     expect_stdout: "2boolean"
 }
+
+issue_4736: {
+    options = {
+        collapse_vars: true,
+        evaluate: true,
+        hoist_vars: true,
+        merge_vars: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a;
+        function f() {
+            (function g() {
+                var b = (a = 0, 1 << 30);
+                var c = (a = 0, console.log(b));
+                var d = c;
+            })(f);
+        }
+        f();
+    }
+    expect: {
+        (function() {
+            (function() {
+                0,
+                console.log(1073741824);
+            })();
+        })();
+    }
+    expect_stdout: "1073741824"
+}
+
+issue_4839: {
+    options = {
+        evaluate: true,
+        hoist_vars: true,
+        keep_fargs: false,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var o = function(a, b) {
+            return b && b;
+        }("foo");
+        for (var k in o)
+            throw "FAIL";
+        console.log("PASS");
+    }
+    expect: {
+        var k, o = void 0;
+        for (k in o)
+            throw "FAIL";
+        console.log("PASS");
+    }
+    expect_stdout: "PASS"
+}
+
+issue_4859: {
+    options = {
+        evaluate: true,
+        hoist_vars: true,
+        keep_infinity: true,
+        merge_vars: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        function f(a) {
+            var b = (a = 2, 1 / 0), c = 3;
+            var d = a + b;
+            console.log(d);
+            return f;
+        }
+        f();
+    }
+    expect: {
+        (function f(a) {
+            var d = 1 / 0, d = Infinity;
+            console.log(d);
+            return f;
+        })();
+    }
+    expect_stdout: "Infinity"
+}
+
+issue_4893_1: {
+    options = {
+        collapse_vars: true,
+        evaluate: true,
+        hoist_vars: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        function f() {
+            function g() {}
+            var a = null;
+            var b = null;
+            var c = null;
+            b.p += a = 42;
+            f;
+        }
+        try {
+            f();
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect: {
+        try{
+            (function f() {
+                var b;
+                b = null;
+                b.p += 42;
+                f;
+            })();
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect_stdout: "PASS"
+}
+
+issue_4893_2: {
+    options = {
+        collapse_vars: true,
+        hoist_vars: true,
+        pure_getters: "strict",
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        function f() {
+            function g() {}
+            var a = null;
+            var b = null;
+            var c = null;
+            b.p += a = 42;
+            f;
+        }
+        try {
+            f();
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect: {
+        try{
+            (function() {
+                var b;
+                b = null;
+                b.p += 42;
+            })();
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect_stdout: "PASS"
+}
+
+issue_4898: {
+    options = {
+        collapse_vars: true,
+        evaluate: true,
+        hoist_vars: true,
+        loops: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        do {
+            var b = [ console.log("PASS") ];
+            var c = b;
+        } while (c.p = 0);
+    }
+    expect: {
+        var b;
+        b = [ console.log("PASS") ];
+        b.p = 0;
+    }
+    expect_stdout: "PASS"
+}

test/compress/ie8.js

@@ -2653,7 +2653,9 @@ issue_4019: {
             try {
                 console.log("FAIL");
             } catch (o) {}
-        }, o = (console.log(o.length), ++o);
+        };
+        console.log(o.length),
+        ++o;
     }
     expect_stdout: "0"
 }
@@ -2919,3 +2921,99 @@ issue_4568: {
     }
     expect_stdout: "undefined 1"
 }
+
+issue_4729: {
+    options = {
+        ie8: true,
+        pure_getters: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        try {
+            f;
+        } catch (e) {
+            var a = a && a[function f() {}];
+            console.log("PASS");
+        }
+    }
+    expect: {
+        try {
+            f;
+        } catch (e) {
+            (function f() {});
+            console.log("PASS");
+        }
+    }
+    expect_stdout: "PASS"
+}
+
+issue_4928_1: {
+    options = {
+        ie8: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = function f() {
+            f(a);
+        };
+        console.log(typeof f);
+    }
+    expect: {
+        var a = function f() {
+            f(a);
+        };
+        console.log(typeof f);
+    }
+    expect_stdout: "undefined"
+}
+
+issue_4928_2: {
+    options = {
+        ie8: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        switch (42) {
+          case console:
+            var a = function f() {
+                f(a);
+            };
+          case 42:
+            var a = console.log("PASS");
+        }
+    }
+    expect: {
+        switch (42) {
+          case console:
+            var a = function f() {
+                f(a);
+            };
+          case 42:
+            a = console.log("PASS");
+        }
+    }
+    expect_stdout: "PASS"
+}
+
+issue_4958: {
+    options = {
+        collapse_vars: true,
+        ie8: true,
+    }
+    input: {
+        console.log(function arguments(a) {
+            a = 21;
+            return arguments[0] + 21;
+        }("FAIL"));
+    }
+    expect: {
+        console.log(function arguments(a) {
+            a = 21;
+            return arguments[0] + 21;
+        }("FAIL"));
+    }
+    expect_stdout: "42"
+}

test/compress/imports.js

@@ -23,7 +23,7 @@ keys_only: {
     input: {
         import { as as foo, bar, delete as baz } from "moo";
     }
-    expect_exact: 'import{as as foo,bar as bar,delete as baz}from"moo";'
+    expect_exact: 'import{as as foo,bar,delete as baz}from"moo";'
 }
 
 default_all: {
@@ -37,7 +37,7 @@ default_keys: {
     input: {
         import foo, { bar } from "baz";
     }
-    expect_exact: 'import foo,{bar as bar}from"baz";'
+    expect_exact: 'import foo,{bar}from"baz";'
 }
 
 dynamic: {
@@ -54,13 +54,22 @@ dynamic_nought: {
     expect_exact: "import(foo);"
 }
 
-import_meta: {
+import_meta_1: {
     input: {
         console.log(import.meta, import.meta.url);
     }
     expect_exact: "console.log(import.meta,import.meta.url);"
 }
 
+import_meta_2: {
+    input: {
+        import.meta.url.split("/").forEach(function(part, index) {
+            console.log(index, part);
+        });
+    }
+    expect_exact: 'import.meta.url.split("/").forEach(function(part,index){console.log(index,part)});'
+}
+
 same_quotes: {
     beautify = {
         beautify: true,

test/compress/issue-1202.js

@@ -4,7 +4,7 @@ mangle_keep_fnames_false: {
         keep_fnames: true,
     }
     mangle = {
-        keep_fnames : false,
+        keep_fnames: false,
     }
     input: {
         "use strict";
@@ -30,7 +30,7 @@ mangle_keep_fnames_true: {
         keep_fnames: true,
     }
     mangle = {
-        keep_fnames : true,
+        keep_fnames: true,
     }
     input: {
         "use strict";

test/compress/issue-1261.js

@@ -1,5 +1,6 @@
 pure_function_calls: {
     options = {
+        annotations: true,
         booleans: true,
         comparisons: true,
         conditionals: true,
@@ -60,6 +61,7 @@ pure_function_calls: {
 
 pure_function_calls_toplevel: {
     options = {
+        annotations: true,
         booleans: true,
         comparisons: true,
         conditionals: true,
@@ -126,6 +128,7 @@ pure_function_calls_toplevel: {
 
 should_warn: {
     options = {
+        annotations: true,
         booleans: true,
         conditionals: true,
         evaluate: true,

test/compress/issue-281.js

@@ -426,6 +426,7 @@ wrap_iife_in_return_call: {
 
 pure_annotation_1: {
     options = {
+        annotations: true,
         inline: true,
         side_effects: true,
     }
@@ -439,6 +440,7 @@ pure_annotation_1: {
 
 pure_annotation_2: {
     options = {
+        annotations: true,
         collapse_vars: true,
         inline: true,
         side_effects: true,
@@ -463,15 +465,19 @@ drop_fargs: {
         var a = 1;
         !function(a_1) {
             a++;
-        }(a++ + (a && a.var));
+        }(a++ + (a && console.log(a)));
         console.log(a);
     }
     expect: {
         var a = 1;
-        ++a && a.var, a++;
+        ++a && console.log(a),
+        a++;
         console.log(a);
     }
-    expect_stdout: "3"
+    expect_stdout: [
+        "2",
+        "3",
+    ]
 }
 
 keep_fargs: {
@@ -486,13 +492,17 @@ keep_fargs: {
         var a = 1;
         !function(a_1) {
             a++;
-        }(a++ + (a && a.var));
+        }(a++ + (a && console.log(a)));
         console.log(a);
     }
     expect: {
         var a = 1;
-        ++a && a.var, a++;
+        ++a && console.log(a),
+        a++;
         console.log(a);
     }
-    expect_stdout: "3"
+    expect_stdout: [
+        "2",
+        "3",
+    ]
 }

test/compress/join_vars.js

@@ -1024,7 +1024,7 @@ issue_3856: {
     expect_stdout: "undefined"
 }
 
-issue_3916: {
+issue_3916_1: {
     options = {
         join_vars: true,
     }
@@ -1044,8 +1044,8 @@ issue_3916: {
         var o = {
             p: "PASS",
             __proto__: 42,
-            q: "FAIL",
         };
+        o.q = "FAIL";
         o.__proto__ = {
             p: "FAIL",
             q: "PASS",
@@ -1056,6 +1056,62 @@ issue_3916: {
     expect_stdout: "object PASS true PASS"
 }
 
+issue_3916_2: {
+    options = {
+        join_vars: true,
+    }
+    input: {
+        var log = console.log, o = {};
+        o.p = "FAIL 1";
+        o.__proto__ = {
+            get p() {
+                return "FAIL 2";
+            },
+            set p(u) {
+                log("FAIL 3");
+            },
+            set q(v) {
+                log("PASS 1");
+            },
+            get q() {
+                return "PASS 3";
+            },
+        };
+        o.p = "PASS 2";
+        o.q = "FAIL 4";
+        log(o.p);
+        log(o.q);
+    }
+    expect: {
+        var log = console.log, o = {
+            p: "FAIL 1",
+            __proto__: {
+                get p() {
+                    return "FAIL 2";
+                },
+                set p(u) {
+                    log("FAIL 3");
+                },
+                set q(v) {
+                    log("PASS 1");
+                },
+                get q() {
+                    return "PASS 3";
+                },
+            },
+        };
+        o.p = "PASS 2";
+        o.q = "FAIL 4";
+        log(o.p);
+        log(o.q);
+    }
+    expect_stdout: [
+        "PASS 1",
+        "PASS 2",
+        "PASS 3",
+    ]
+}
+
 assign_var: {
     options = {
         join_vars: true,

test/compress/keep_fargs.js

@@ -117,6 +117,7 @@ issue_1858: {
         collapse_vars: true,
         keep_fargs: false,
         pure_getters: true,
+        reduce_vars: true,
         unused: true,
     }
     input: {

test/compress/let.js

@@ -20,6 +20,39 @@ retain_block: {
     node_version: ">=4"
 }
 
+retain_assignment: {
+    options = {
+        dead_code: true,
+        reduce_vars: true,
+    }
+    input: {
+        "use strict";
+        function f() {
+            return a = 0;
+            let a;
+        }
+        try {
+            f();
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect: {
+        "use strict";
+        function f() {
+            return a = 0;
+            let a;
+        }
+        try {
+            f();
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
 retain_catch: {
     options = {
         dead_code: true,
@@ -359,7 +392,7 @@ reduce_block_2_toplevel: {
     node_version: ">=4"
 }
 
-reduce_vars: {
+reduce_vars_1: {
     options = {
         evaluate: true,
         reduce_vars: true,
@@ -381,6 +414,86 @@ reduce_vars: {
     node_version: ">=4"
 }
 
+reduce_vars_2: {
+    options = {
+        reduce_funcs: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        "use strict";
+        (function() {
+            function f() {
+                console.log(typeof a);
+            }
+            for (let a in [ 42 ])
+                f();
+        })();
+    }
+    expect: {
+        "use strict";
+        (function() {
+            function f() {
+                console.log(typeof a);
+            }
+            for (let a in [ 42 ])
+                f();
+        })();
+    }
+    expect_stdout: "undefined"
+    node_version: ">=4"
+}
+
+reduce_vars_3: {
+    options = {
+        reduce_funcs: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        "use strict";
+        (function(a) {
+            let i = 1;
+            function f() {
+                i = 0;
+            }
+            for (let i = 0, x = 0; i < a.length; i++, x++) {
+                if (x != i) {
+                    console.log("FAIL");
+                    break;
+                }
+                f();
+                console.log(a[i]);
+            }
+            console.log(i);
+        })([ 4, 2 ]);
+    }
+    expect: {
+        "use strict";
+        (function(a) {
+            let i = 1;
+            function f() {
+                i = 0;
+            }
+            for (let i = 0, x = 0; i < a.length; i++, x++) {
+                if (x != i) {
+                    console.log("FAIL");
+                    break;
+                }
+                f();
+                console.log(a[i]);
+            }
+            console.log(i);
+        })([ 4, 2 ]);
+    }
+    expect_stdout: [
+        "4",
+        "2",
+        "0",
+    ]
+    node_version: ">=4"
+}
+
 hoist_props: {
     options = {
         hoist_props: true,
@@ -456,6 +569,38 @@ loop_block_2: {
     node_version: ">=4"
 }
 
+do_break: {
+    options = {
+        loops: true,
+    }
+    input: {
+        "use strict";
+        try {
+            do {
+                if (a)
+                    break;
+                let a;
+            } while (!console);
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect: {
+        "use strict";
+        try {
+            do {
+                if (a)
+                    break;
+                let a;
+            } while (!console);
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
 do_continue: {
     options = {
         loops: true,
@@ -516,6 +661,82 @@ dead_block_after_return: {
     node_version: ">=4"
 }
 
+if_return_1: {
+    options = {
+        if_return: true,
+    }
+    input: {
+        "use strict";
+        function f(a) {
+            function g() {
+                return b = "PASS";
+            }
+            if (a)
+                return g();
+            let b;
+            return g();
+        };
+        console.log(f());
+    }
+    expect: {
+        "use strict";
+        function f(a) {
+            function g() {
+                return b = "PASS";
+            }
+            if (a)
+                return g();
+            let b;
+            return g();
+        };
+        console.log(f());
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
+if_return_2: {
+    options = {
+        if_return: true,
+    }
+    input: {
+        "use strict";
+        function f(a) {
+            function g() {
+                return b = "FAIL";
+            }
+            if (a)
+                return g();
+            let b;
+            return g();
+        };
+        try {
+            console.log(f(42));
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect: {
+        "use strict";
+        function f(a) {
+            function g() {
+                return b = "FAIL";
+            }
+            if (a)
+                return g();
+            let b;
+            return g();
+        };
+        try {
+            console.log(f(42));
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
 do_if_continue_1: {
     options = {
         if_return: true,
@@ -610,6 +831,28 @@ drop_unused: {
     node_version: ">=4"
 }
 
+default_init: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        sequences: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        "use strict";
+        let a;
+        a = "PASS";
+        console.log(a);
+    }
+    expect: {
+        "use strict";
+        console.log("PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
 issue_4191: {
     options = {
         functions: true,
@@ -795,6 +1038,7 @@ issue_4210: {
 issue_4212_1: {
     options = {
         dead_code: true,
+        reduce_vars: true,
     }
     input: {
         "use strict";
@@ -1404,3 +1648,67 @@ issue_4691: {
     expect_stdout: "PASS"
     node_version: ">=4"
 }
+
+issue_4848: {
+    options = {
+        if_return: true,
+    }
+    input: {
+        "use strict";
+        function f(a) {
+            a(function() {
+                console.log(b);
+            });
+            if (!console)
+                return;
+            let b = "PASS";
+        }
+        var g;
+        f(function(h) {
+            g = h;
+        });
+        g();
+    }
+    expect: {
+        "use strict";
+        function f(a) {
+            a(function() {
+                console.log(b);
+            });
+            if (!console)
+                return;
+            let b = "PASS";
+        }
+        var g;
+        f(function(h) {
+            g = h;
+        });
+        g();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
+issue_4985: {
+    options = {
+        hoist_props: true,
+        reduce_vars: true,
+        toplevel: true,
+    }
+    input: {
+        "use strict";
+        let a = { p: 42 };
+        console.log(function() {
+            a;
+        }());
+    }
+    expect: {
+        "use strict";
+        let a = { p: 42 };
+        console.log(function() {
+            a;
+        }());
+    }
+    expect_stdout: "undefined"
+    node_version: ">=4"
+}

test/compress/loops.js

@@ -829,6 +829,18 @@ empty_for_in_prop_init: {
 }
 
 for_of: {
+    input: {
+        var a = [ "PASS", 42 ];
+        a.p = "FAIL";
+        for (a of (null, a))
+            console.log(a);
+    }
+    expect_exact: 'var a=["PASS",42];a.p="FAIL";for(a of(null,a))console.log(a);'
+    expect_stdout: true
+    node_version: ">=0.12"
+}
+
+for_async_of: {
     input: {
         var async = [ "PASS", 42 ];
         async.p = "FAIL";
@@ -836,11 +848,22 @@ for_of: {
             console.log(async);
     }
     expect_exact: 'var async=["PASS",42];async.p="FAIL";for(async of(null,async))console.log(async);'
-    expect_stdout: [
+    expect_stdout: true
-        "PASS",
+    node_version: ">=0.12 <16"
-        "42",
+}
-    ]
+
-    node_version: ">=0.12"
+for_of_regexp: {
+    input: {
+        for (var a of /foo/);
+    }
+    expect_exact: "for(var a of/foo/);"
+}
+
+for_await_of_regexp: {
+    input: {
+        for await (var a of /foo/);
+    }
+    expect_exact: "for await(var a of/foo/);"
 }
 
 issue_3631_1: {

test/compress/merge_vars.js

@@ -2620,9 +2620,9 @@ issue_4126_1: {
             try {
                 console.log("PASS");
             } catch (e) {
-                var b = a;
+                var c = a;
             } finally {
-                var c = b;
+                var c = c;
             }
             console.log(c);
         }
@@ -3239,3 +3239,142 @@ issue_4653: {
         "0",
     ]
 }
+
+issue_4759: {
+    options = {
+        merge_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var i = 2, a = 1, b, c, d;
+        while (i--) {
+            try {
+                if (1 != b) {
+                    d = [];
+                    null.p;
+                    c = d;
+                } else {
+                    b = 0;
+                    a = c;
+                }
+            } catch (e) {}
+            b = a;
+        }
+        console.log(a);
+    }
+    expect: {
+        var i = 2, a = 1, b, c, d;
+        while (i--) {
+            try {
+                if (1 != b) {
+                    d = [];
+                    null.p;
+                    c = d;
+                } else {
+                    b = 0;
+                    a = c;
+                }
+            } catch (e) {}
+            b = a;
+        }
+        console.log(a);
+    }
+    expect_stdout: "undefined"
+}
+
+issue_4761: {
+    options = {
+        merge_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var a = "FAIL", b;
+        try {
+            !a && --a && (b = 0)[console] || console.log(b);
+        } catch (e) {}
+    }
+    expect: {
+        var a = "FAIL", b;
+        try {
+            !a && --a && (b = 0)[console] || console.log(b);
+        } catch (e) {}
+    }
+    expect_stdout: "undefined"
+}
+
+issue_4956_1: {
+    options = {
+        merge_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var a, b;
+        function f(c) {
+            switch (c) {
+              case 0:
+                a = { p: 42 };
+
+              case 1:
+                b = a.p;
+                console.log(b);
+            }
+        }
+        f(0);
+        f(1);
+    }
+    expect: {
+        var a, b;
+        function f(c) {
+            switch (c) {
+              case 0:
+                a = { p: 42 };
+
+              case 1:
+                b = a.p;
+                console.log(b);
+            }
+        }
+        f(0);
+        f(1);
+    }
+    expect_stdout: [
+        "42",
+        "42",
+    ]
+}
+
+issue_4956_2: {
+    options = {
+        merge_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var a, b;
+        function f(c) {
+            if (0 == c) {
+                console;
+                a = { p: 42 };
+            }
+            b = a.p;
+            if (1 == c)
+                console.log(b);
+        }
+        f(0);
+        f(1);
+    }
+    expect: {
+        var a, b;
+        function f(c) {
+            if (0 == c) {
+                console;
+                a = { p: 42 };
+            }
+            b = a.p;
+            if (1 == c)
+                console.log(b);
+        }
+        f(0);
+        f(1);
+    }
+    expect_stdout: "42"
+}

test/compress/numbers.js

@@ -1,3 +1,10 @@
+literal_infinity: {
+    input: {
+        console.log(2e308, -1e2345);
+    }
+    expect_exact: "console.log(1/0,-(1/0));"
+}
+
 parentheses_for_prototype_functions: {
     beautify = {
         beautify: true,
@@ -97,6 +104,40 @@ parentheses_for_prototype_functions_galio: {
     expect_stdout: true
 }
 
+octal: {
+    beautify = {
+        beautify: true,
+    }
+    input: {
+        (function() {
+            console.log(052);
+            console.log(-052);
+
+            console.log(018);
+            console.log(-018);
+
+            console.log(052.toFixed(0));
+            console.log(-052.toFixed(0));
+
+            console.log(018..toFixed(0));
+            console.log(-018..toFixed(0));
+        })();
+    }
+    expect_exact: [
+        "(function() {",
+        "    console.log(42);",
+        "    console.log(-42);",
+        "    console.log(18);",
+        "    console.log(-18);",
+        "    console.log(42..toFixed(0));",
+        "    console.log(-42..toFixed(0));",
+        "    console.log(18..toFixed(0));",
+        "    console.log(-18..toFixed(0));",
+        "})();",
+    ]
+    expect_stdout: true
+}
+
 comparisons: {
     options = {
         comparisons: true,

test/compress/optional-chains.js

@@ -0,0 +1,307 @@
+call: {
+    input: {
+        console.log?.(undefined?.(console.log("FAIL")));
+    }
+    expect_exact: 'console.log?.((void 0)?.(console.log("FAIL")));'
+    expect_stdout: "undefined"
+    node_version: ">=14"
+}
+
+dot: {
+    input: {
+        console?.log((void 0)?.p);
+    }
+    expect_exact: "console?.log((void 0)?.p);"
+    expect_stdout: "undefined"
+    node_version: ">=14"
+}
+
+dot_in: {
+    input: {
+        var o = { in: 42 };
+        console.log(o.in, o?.in);
+    }
+    expect_exact: "var o={in:42};console.log(o.in,o?.in);"
+    expect_stdout: "42 42"
+    node_version: ">=14"
+}
+
+sub: {
+    input: {
+        console?.["log"](null?.[console.log("FAIL")]);
+    }
+    expect_exact: 'console?.["log"](null?.[console.log("FAIL")]);'
+    expect_stdout: "undefined"
+    node_version: ">=14"
+}
+
+ternary_decimal: {
+    input: {
+        null ? .42 : console.log("PASS");
+    }
+    expect_exact: 'null?.42:console.log("PASS");'
+    expect_stdout: "PASS"
+}
+
+assign_parentheses_call: {
+    input: {
+        var o = {};
+        ((() => o)?.()).p = "PASS";
+        console.log(o.p);
+    }
+    expect_exact: 'var o={};((()=>o)?.()).p="PASS";console.log(o.p);'
+    expect_stdout: "PASS"
+    node_version: ">=14"
+}
+
+assign_parentheses_dot: {
+    input: {
+        (console?.log).name.p = console.log("PASS");
+    }
+    expect_exact: '(console?.log.name).p=console.log("PASS");'
+    expect_stdout: "PASS"
+    node_version: ">=14"
+}
+
+assign_no_parentheses: {
+    input: {
+        console[console.log?.("PASS")] = 42;
+    }
+    expect_exact: 'console[console.log?.("PASS")]=42;'
+    expect_stdout: "PASS"
+    node_version: ">=14"
+}
+
+unary_parentheses: {
+    input: {
+        var o = { p: 41 };
+        (function() {
+            return o;
+        }?.()).p++;
+        console.log(o.p);
+    }
+    expect_exact: "var o={p:41};(function(){return o}?.()).p++;console.log(o.p);"
+    expect_stdout: "42"
+    node_version: ">=14"
+}
+
+collapse_vars_1: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        var a;
+        A = 42;
+        a?.[42];
+        console.log(typeof A);
+    }
+    expect: {
+        var a;
+        A = 42;
+        a?.[42];
+        console.log(typeof A);
+    }
+    expect_stdout: "number"
+    node_version: ">=14"
+}
+
+collapse_vars_2: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        var a;
+        A = 42;
+        a?.(42);
+        console.log(typeof A);
+    }
+    expect: {
+        var a;
+        A = 42;
+        a?.(42);
+        console.log(typeof A);
+    }
+    expect_stdout: "number"
+    node_version: ">=14"
+}
+
+properties: {
+    options = {
+        evaluate: true,
+        properties: true,
+    }
+    input: {
+        var a;
+        console.log(a?.["FAIL"]);
+    }
+    expect: {
+        var a;
+        console.log(a?.FAIL);
+    }
+    expect_stdout: "undefined"
+    node_version: ">=14"
+}
+
+reduce_vars_1: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var a = 1;
+        null?.[a = 0];
+        console.log(a ? "PASS" : "FAIL");
+    }
+    expect: {
+        var a = 1;
+        null?.[a = 0];
+        console.log(a ? "PASS" : "FAIL");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=14"
+}
+
+reduce_vars_2: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var a = 1;
+        null?.(a = 0);
+        console.log(a ? "PASS" : "FAIL");
+    }
+    expect: {
+        var a = 1;
+        null?.(a = 0);
+        console.log(a ? "PASS" : "FAIL");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=14"
+}
+
+side_effects: {
+    options = {
+        side_effects: true,
+    }
+    input: {
+        var a;
+        a?.[a = "FAIL"];
+        console.log(a);
+    }
+    expect: {
+        var a;
+        a?.[a = "FAIL"];
+        console.log(a);
+    }
+    expect_stdout: "undefined"
+    node_version: ">=14"
+}
+
+trim_1: {
+    options = {
+        evaluate: true,
+        optional_chains: true,
+        reduce_vars: true,
+        unsafe: true,
+    }
+    input: {
+        (function(a, b) {
+            console?.log?.(a?.p, b?.[console.log("FAIL")]);
+        })?.({ p: "PASS" });
+    }
+    expect: {
+        (function(a, b) {
+            console?.log?.(a.p, void 0);
+        })({ p: "PASS" });
+    }
+    expect_stdout: "PASS undefined"
+    node_version: ">=14"
+}
+
+trim_2: {
+    options = {
+        evaluate: true,
+        optional_chains: true,
+        side_effects: true,
+    }
+    input: {
+        (void console.log("PASS"))?.[console.log("FAIL")];
+    }
+    expect: {
+        console.log("PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=14"
+}
+
+issue_4906: {
+    options = {
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        do {
+            var a = a?.[42];
+        } while (console.log("PASS"));
+    }
+    expect: {
+        do {} while (console.log("PASS"));
+    }
+    expect_stdout: "PASS"
+    node_version: ">=14"
+}
+
+issue_4928: {
+    options = {
+        ie8: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = a?.[function f() {
+            f(a);
+        }];
+        console.log(typeof f);
+    }
+    expect: {
+        var a = a?.[function f() {
+            f(a);
+        }];
+        console.log(typeof f);
+    }
+    expect_stdout: "undefined"
+    node_version: ">=14"
+}
+
+issue_4947_1: {
+    options = {
+        conditionals: true,
+    }
+    input: {
+        console.log(console.foo ? 42..p : console.bar?.p);
+    }
+    expect: {
+        console.log(console.foo ? 42..p : console.bar?.p);
+    }
+    expect_stdout: "undefined"
+    node_version: ">=14"
+}
+
+issue_4947_2: {
+    options = {
+        conditionals: true,
+    }
+    input: {
+        var log = console.log, fail;
+        log("PASS") ? log(42) : fail?.(42);
+    }
+    expect: {
+        var log = console.log, fail;
+        log("PASS") ? log(42) : fail?.(42);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=14"
+}

test/compress/properties.js

@@ -1400,3 +1400,66 @@ object_super: {
     expect_stdout: "PASS"
     node_version: ">=4"
 }
+
+issue_4831_1: {
+    options = {
+        properties: true,
+    }
+    input: {
+        console.log({
+            f() {
+                return arguments;
+            },
+        }.f("PASS")[0]);
+    }
+    expect: {
+        console.log([
+            function() {
+                return arguments;
+            },
+        ][0]("PASS")[0]);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
+issue_4831_2: {
+    options = {
+        properties: true,
+    }
+    input: {
+        var f = {
+            f() {
+                return arguments;
+            },
+        }.f;
+        console.log(f("PASS")[0]);
+    }
+    expect: {
+        var f = {
+            f() {
+                return arguments;
+            },
+        }.f;
+        console.log(f("PASS")[0]);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
+issue_4888: {
+    options = {
+        properties: true,
+    }
+    input: {
+        console.log(typeof {
+            __proto__: 42,
+        }.__proto__);
+    }
+    expect: {
+        console.log(typeof {
+            __proto__: 42,
+        }.__proto__);
+    }
+    expect_stdout: "object"
+}

test/compress/pure_funcs.js

@@ -133,7 +133,7 @@ conditional: {
 relational: {
     options = {
         pure_funcs: [ "foo" ],
-        side_effects :true,
+        side_effects: true,
     }
     input: {
         foo() in new foo();
@@ -158,7 +158,7 @@ relational: {
 arithmetic: {
     options = {
         pure_funcs: [ "foo" ],
-        side_effects :true,
+        side_effects: true,
     }
     input: {
         foo() + foo();
@@ -183,7 +183,7 @@ arithmetic: {
 boolean_and: {
     options = {
         pure_funcs: [ "foo" ],
-        side_effects :true,
+        side_effects: true,
     }
     input: {
         foo() && foo();
@@ -208,7 +208,7 @@ boolean_and: {
 boolean_or: {
     options = {
         pure_funcs: [ "foo" ],
-        side_effects :true,
+        side_effects: true,
     }
     input: {
         foo() || foo();
@@ -233,7 +233,7 @@ boolean_or: {
 assign: {
     options = {
         pure_funcs: [ "foo" ],
-        side_effects :true,
+        side_effects: true,
     }
     input: {
         var a;
@@ -256,7 +256,7 @@ assign: {
 unary: {
     options = {
         pure_funcs: [ "foo" ],
-        side_effects :true,
+        side_effects: true,
     }
     input: {
         typeof foo();
@@ -294,248 +294,6 @@ unary: {
     }
 }
 
-issue_2629_1: {
-    options = {
-        side_effects: true,
-    }
-    beautify = {
-        comments: "all",
-    }
-    input: {
-        /*@__PURE__*/ a();
-        /*@__PURE__*/ (b());
-        (/*@__PURE__*/ c)();
-        (/*@__PURE__*/ d());
-    }
-    expect_exact: [
-        "/* */c();",
-    ]
-}
-
-issue_2629_2: {
-    options = {
-        side_effects: true,
-    }
-    beautify = {
-        comments: "all",
-    }
-    input: {
-        /*@__PURE__*/ a(1)(2)(3);
-        /*@__PURE__*/ (b(1))(2)(3);
-        /*@__PURE__*/ (c(1)(2))(3);
-        /*@__PURE__*/ (d(1)(2)(3));
-        (/*@__PURE__*/ e)(1)(2)(3);
-        (/*@__PURE__*/ f(1))(2)(3);
-        (/*@__PURE__*/ g(1)(2))(3);
-        (/*@__PURE__*/ h(1)(2)(3));
-    }
-    expect_exact: [
-        "/* */e(1)(2)(3);",
-        "/* */f(1)(2)(3);",
-        "/* */g(1)(2)(3);",
-    ]
-}
-
-issue_2629_3: {
-    options = {
-        side_effects: true,
-    }
-    beautify = {
-        comments: "all",
-    }
-    input: {
-        /*@__PURE__*/ a.x(1).y(2).z(3);
-        /*@__PURE__*/ (b.x)(1).y(2).z(3);
-        /*@__PURE__*/ (c.x(1)).y(2).z(3);
-        /*@__PURE__*/ (d.x(1).y)(2).z(3);
-        /*@__PURE__*/ (e.x(1).y(2)).z(3);
-        /*@__PURE__*/ (f.x(1).y(2).z)(3);
-        /*@__PURE__*/ (g.x(1).y(2).z(3));
-        (/*@__PURE__*/ h).x(1).y(2).z(3);
-        (/*@__PURE__*/ i.x)(1).y(2).z(3);
-        (/*@__PURE__*/ j.x(1)).y(2).z(3);
-        (/*@__PURE__*/ k.x(1).y)(2).z(3);
-        (/*@__PURE__*/ l.x(1).y(2)).z(3);
-        (/*@__PURE__*/ m.x(1).y(2).z)(3);
-        (/*@__PURE__*/ n.x(1).y(2).z(3));
-    }
-    expect_exact: [
-        "/* */h.x(1).y(2).z(3);",
-        "/* */i.x(1).y(2).z(3);",
-        "/* */j.x(1).y(2).z(3);",
-        "/* */k.x(1).y(2).z(3);",
-        "/* */l.x(1).y(2).z(3);",
-        "/* */m.x(1).y(2).z(3);",
-    ]
-}
-
-issue_2629_4: {
-    options = {
-        side_effects: true,
-    }
-    input: {
-        (/*@__PURE__*/ x(), y());
-        (w(), /*@__PURE__*/ x(), y());
-    }
-    expect: {
-        y();
-        w(), y();
-    }
-}
-
-issue_2629_5: {
-    options = {
-        side_effects: true,
-    }
-    input: {
-        [ /*@__PURE__*/ x() ];
-        [ /*@__PURE__*/ x(), y() ];
-        [ w(), /*@__PURE__*/ x(), y() ];
-    }
-    expect: {
-        y();
-        w(), y();
-    }
-}
-
-issue_2638: {
-    options = {
-        side_effects: true,
-    }
-    beautify = {
-        comments: "all",
-    }
-    input: {
-        /*@__PURE__*/(g() || h())(x(), y());
-        (/*@__PURE__*/ (a() || b()))(c(), d());
-    }
-    expect_exact: [
-        "/* */x(),y();",
-        "/* */(a()||b())(c(),d());",
-    ]
-}
-
-issue_2705_1: {
-    options = {
-        side_effects: true,
-    }
-    beautify = {
-        comments: "all",
-    }
-    input: {
-        /*@__PURE__*/ new a();
-        /*@__PURE__*/ (new b());
-        new (/*@__PURE__*/ c)();
-        (/*@__PURE__*/ new d());
-    }
-    expect_exact: [
-        "new/* */c;",
-    ]
-}
-
-issue_2705_2: {
-    options = {
-        side_effects: true,
-    }
-    beautify = {
-        comments: "all",
-    }
-    input: {
-        /*@__PURE__*/ new a(1)(2)(3);
-        /*@__PURE__*/ new (b(1))(2)(3);
-        /*@__PURE__*/ new (c(1)(2))(3);
-        /*@__PURE__*/ new (d(1)(2)(3));
-        new (/*@__PURE__*/ e)(1)(2)(3);
-        (/*@__PURE__*/ new f(1))(2)(3);
-        (/*@__PURE__*/ new g(1)(2))(3);
-        (/*@__PURE__*/ new h(1)(2)(3));
-    }
-    expect_exact: [
-        "new/* */e(1)(2)(3);",
-        "/* */new f(1)(2)(3);",
-        "/* */new g(1)(2)(3);",
-    ]
-}
-
-issue_2705_3: {
-    options = {
-        side_effects: true,
-    }
-    beautify = {
-        comments: "all",
-    }
-    input: {
-        /*@__PURE__*/ new a.x(1).y(2).z(3);
-        /*@__PURE__*/ new (b.x)(1).y(2).z(3);
-        /*@__PURE__*/ new (c.x(1)).y(2).z(3);
-        /*@__PURE__*/ new (d.x(1).y)(2).z(3);
-        /*@__PURE__*/ new (e.x(1).y(2)).z(3);
-        /*@__PURE__*/ new (f.x(1).y(2).z)(3);
-        /*@__PURE__*/ new (g.x(1).y(2).z(3));
-        new (/*@__PURE__*/ h).x(1).y(2).z(3);
-        /* */ new (/*@__PURE__*/ i.x)(1).y(2).z(3);
-        (/*@__PURE__*/ new j.x(1)).y(2).z(3);
-        (/*@__PURE__*/ new k.x(1).y)(2).z(3);
-        (/*@__PURE__*/ new l.x(1).y(2)).z(3);
-        (/*@__PURE__*/ new m.x(1).y(2).z)(3);
-        (/*@__PURE__*/ new n.x(1).y(2).z(3));
-    }
-    expect_exact: [
-        "new/* */h.x(1).y(2).z(3);",
-        "/* */new/* */i.x(1).y(2).z(3);",
-        "/* */new j.x(1).y(2).z(3);",
-        "/* */new k.x(1).y(2).z(3);",
-        "/* */new l.x(1).y(2).z(3);",
-        "/* */new m.x(1).y(2).z(3);",
-    ]
-}
-
-issue_2705_4: {
-    options = {
-        side_effects: true,
-    }
-    input: {
-        (/*@__PURE__*/ new x(), y());
-        (w(), /*@__PURE__*/ new x(), y());
-    }
-    expect: {
-        y();
-        w(), y();
-    }
-}
-
-issue_2705_5: {
-    options = {
-        side_effects: true,
-    }
-    input: {
-        [ /*@__PURE__*/ new x() ];
-        [ /*@__PURE__*/ new x(), y() ];
-        [ w(), /*@__PURE__*/ new x(), y() ];
-    }
-    expect: {
-        y();
-        w(), y();
-    }
-}
-
-issue_2705_6: {
-    options = {
-        side_effects: true,
-    }
-    beautify = {
-        comments: "all",
-    }
-    input: {
-        /*@__PURE__*/new (g() || h())(x(), y());
-        /* */ new (/*@__PURE__*/ (a() || b()))(c(), d());
-    }
-    expect_exact: [
-        "/* */x(),y();",
-        "/* */new(/* */a()||b())(c(),d());",
-    ]
-}
-
 issue_3065_1: {
     options = {
         inline: true,
@@ -680,130 +438,3 @@ issue_3325_2: {
     }
     expect_stdout: "PASS"
 }
-
-issue_3858: {
-    options = {
-        collapse_vars: true,
-        inline: true,
-        keep_fargs: false,
-        unused: true,
-    }
-    input: {
-        var f = function(a) {
-            return /*@__PURE__*/ function(b) {
-                console.log(b);
-            }(a);
-        };
-        f("PASS");
-    }
-    expect: {
-        var f = function(a) {
-            return function() {
-                console.log(a);
-            }();
-        };
-        f("PASS");
-    }
-    expect_stdout: "PASS"
-}
-
-inline_pure_call_1: {
-    options = {
-        collapse_vars: true,
-        inline: true,
-        keep_fargs: false,
-        reduce_vars: true,
-        sequences: true,
-        side_effects: true,
-        toplevel: true,
-        unused: true,
-    }
-    input: {
-        var f = function(a) {
-            return /*@__PURE__*/ function(b) {
-                console.log(b);
-            }(a);
-        };
-        f("PASS");
-    }
-    expect: {}
-}
-
-inline_pure_call_2: {
-    options = {
-        collapse_vars: true,
-        inline: true,
-        keep_fargs: false,
-        reduce_vars: true,
-        sequences: true,
-        side_effects: true,
-        toplevel: true,
-        unused: true,
-    }
-    input: {
-        var f = function(a) {
-            return /*@__PURE__*/ function(b) {
-                console.log(b);
-            }(a);
-        };
-        var a = f("PASS");
-    }
-    expect: {}
-}
-
-inline_pure_call_3: {
-    options = {
-        collapse_vars: true,
-        evaluate: true,
-        inline: true,
-        keep_fargs: false,
-        passes: 2,
-        reduce_vars: true,
-        toplevel: true,
-        unused: true,
-    }
-    input: {
-        var f = function(a) {
-            return /*@__PURE__*/ function(b) {
-                console.log(b);
-            }(a);
-        };
-        var a = f("PASS");
-        console.log(a);
-    }
-    expect: {
-        var a = function() {
-            console.log("PASS");
-        }();
-        console.log(a);
-    }
-    expect_stdout: [
-        "PASS",
-        "undefined",
-    ]
-}
-
-inline_pure_call_4: {
-    options = {
-        evaluate: true,
-        reduce_vars: true,
-        toplevel: true,
-        unused: true,
-    }
-    input: {
-        var a = /*@__PURE__*/ function() {
-            return console.log("PASS"), 42;
-        }();
-        console.log(a);
-    }
-    expect: {
-        var a = function() {
-            return console.log("PASS"), 42;
-        }();
-        console.log(a);
-    }
-    expect_stdout: [
-        "PASS",
-        "42",
-    ]
-}

test/compress/pure_getters.js

@@ -1220,13 +1220,110 @@ drop_arguments: {
     expect_stdout: "PASS"
 }
 
+lvalues_def: {
+    options = {
+        collapse_vars: true,
+        pure_getters: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        var a = 0, b = 1;
+        var a = b++, b = +function() {}();
+        a && a[a++];
+        console.log(a, b);
+    }
+    expect: {
+        var a = 0, b = 1;
+        a = b++, b = +void 0;
+        a && a++;
+        console.log(a, b);
+    }
+    expect_stdout: true
+}
+
+side_effects_assign: {
+    options = {
+        evaluate: true,
+        pure_getters: true,
+        reduce_funcs: true,
+        reduce_vars: true,
+        sequences: true,
+        side_effects: true,
+        toplevel: true,
+    }
+    input: {
+        var a = typeof void (a && a.in == 1, 0);
+        console.log(a);
+    }
+    expect: {
+        var a = "undefined";
+        console.log(a);
+    }
+    expect_stdout: "undefined"
+}
+
+issue_2062: {
+    options = {
+        booleans: true,
+        collapse_vars: true,
+        conditionals: true,
+        pure_getters: true,
+        side_effects: true,
+    }
+    input: {
+        var a = 1;
+        if ([ a || a++ + a--, a++ + a--, a && a.var ]);
+        console.log(a);
+    }
+    expect: {
+        var a = 1;
+        a || (a++, a--), a++, a--;
+        console.log(a);
+    }
+    expect_stdout: "1"
+}
+
+issue_2878: {
+    options = {
+        collapse_vars: true,
+        pure_getters: true,
+        sequences: true,
+    }
+    input: {
+        var c = 0;
+        (function(a, b) {
+            function f2() {
+                if (a) c++;
+            }
+            b = f2();
+            a = 1;
+            b && b.b;
+            f2();
+        })();
+        console.log(c);
+    }
+    expect: {
+        var c = 0;
+        (function(a, b) {
+            function f2() {
+                if (a) c++;
+            }
+            b = f2(),
+            a = 1,
+            f2();
+        })(),
+        console.log(c);
+    }
+    expect_stdout: "1"
+}
+
 issue_3427: {
     options = {
-        assignments: true,
+        evaluate: true,
-        collapse_vars: true,
         inline: true,
-        passes: 2,
         pure_getters: "strict",
+        reduce_vars: true,
         sequences: true,
         side_effects: true,
         toplevel: true,
@@ -1242,6 +1339,74 @@ issue_3427: {
     expect_stdout: true
 }
 
+issue_3490_1: {
+    options = {
+        conditionals: true,
+        dead_code: true,
+        inline: true,
+        pure_getters: true,
+        sequences: true,
+        side_effects: true,
+        toplevel: true,
+    }
+    input: {
+        var b = 42, c = "FAIL";
+        if ({
+            3: function() {
+                var a;
+                return (a && a.p) < this;
+            }(),
+        }) c = "PASS";
+        if (b) while ("" == typeof d);
+        console.log(c, b);
+    }
+    expect: {
+        var b = 42, c = "FAIL";
+        if (function() {
+            var a;
+        }(), c = "PASS", b) while ("" == typeof d);
+        console.log(c, b);
+    }
+    expect_stdout: "PASS 42"
+}
+
+issue_4135: {
+    options = {
+        evaluate: true,
+        inline: true,
+        merge_vars: true,
+        pure_getters: true,
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = 0, b = 0;
+        --b;
+        a++;
+        if (!a)
+            var c = function() {
+                var d = 0;
+                function f() {
+                    d && d.p;
+                }
+                f();
+                this;
+            }(a++);
+        console.log(a, b, c);
+    }
+    expect: {
+        var a = 0;
+        0;
+        a++;
+        if (!a)
+            var c = void a++;
+        console.log(a, -1, c);
+    }
+    expect_stdout: "1 -1 undefined"
+}
+
 issue_4440: {
     options = {
         pure_getters: "strict",
@@ -1270,3 +1435,232 @@ issue_4440: {
     }
     expect_stdout: "PASS"
 }
+
+issue_4730_1: {
+    options = {
+        pure_getters: true,
+        side_effects: true,
+    }
+    input: {
+        var a;
+        console.log("PASS") + (a && a[a.p]);
+    }
+    expect: {
+        var a;
+        console.log("PASS");
+    }
+    expect_stdout: "PASS"
+}
+
+issue_4730_2: {
+    options = {
+        pure_getters: true,
+        side_effects: true,
+    }
+    input: {
+        var a;
+        !console.log("PASS") || a && a[a.p];
+    }
+    expect: {
+        var a;
+        console.log("PASS");
+    }
+    expect_stdout: "PASS"
+}
+
+issue_4751: {
+    options = {
+        pure_getters: true,
+        side_effects: true,
+    }
+    input: {
+        var o = {
+            get p() {
+                console.log("PASS");
+            },
+        };
+        o && o.p;
+    }
+    expect: {
+        var o = {
+            get p() {
+                console.log("PASS");
+            },
+        };
+    }
+}
+
+super_toString: {
+    options = {
+        pure_getters: true,
+        unsafe: true,
+    }
+    input: {
+        console.log({
+            f() {
+                return super.toString();
+            },
+        }.f());
+    }
+    expect: {
+        console.log({
+            f() {
+                return super.toString();
+            },
+        }.f());
+    }
+    expect_stdout: "[object Object]"
+    node_version: ">=4"
+}
+
+this_toString: {
+    options = {
+        pure_getters: true,
+        unsafe: true,
+    }
+    input: {
+        console.log({
+            f() {
+                return this.toString();
+            },
+        }.f());
+    }
+    expect: {
+        console.log({
+            f() {
+                return "" + this;
+            },
+        }.f());
+    }
+    expect_stdout: "[object Object]"
+    node_version: ">=4"
+}
+
+issue_4803: {
+    options = {
+        hoist_vars: true,
+        pure_getters: "strict",
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+    }
+    input: {
+        var o = {
+            get f() {
+                console.log("PASS");
+            },
+        } || 42;
+        for (var k in o)
+            o[k];
+    }
+    expect: {
+        var k, o = {
+            get f() {
+                console.log("PASS");
+            },
+        } || 42;
+        for (k in o)
+            o[k];
+    }
+    expect_stdout: "PASS"
+}
+
+nested_property_assignments_1: {
+    options = {
+        pure_getters: "strict",
+        reduce_vars: true,
+        sequences: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var f;
+        ((f = function() {
+            console.log("FAIL");
+        }).p = f).q = console.log("PASS");
+    }
+    expect: {
+        console.log("PASS");
+    }
+    expect_stdout: "PASS"
+}
+
+nested_property_assignments_2: {
+    options = {
+        pure_getters: "strict",
+        unused: true,
+    }
+    input: {
+        var o = {};
+        (function() {
+            var a;
+            (o.p = a = {}).q = "PASS";
+        })();
+        console.log(o.p.q);
+    }
+    expect: {
+        var o = {};
+        (function() {
+            (o.p = {}).q = "PASS";
+        })();
+        console.log(o.p.q);
+    }
+    expect_stdout: "PASS"
+}
+
+nested_property_assignments_3: {
+    options = {
+        collapse_vars: true,
+        pure_getters: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        var o = { p: {} };
+        (function(a) {
+            console && a;
+            if (console) {
+                a = a.p;
+                a.q = a;
+            }
+        })(o);
+        console.log(o.p.q === o.p ? "PASS" : "FAIL");
+    }
+    expect: {
+        var o = { p: {} };
+        (function(a) {
+            console;
+            if (console)
+                (a = a.p).q = a;
+        })(o);
+        console.log(o.p.q === o.p ? "PASS" : "FAIL");
+    }
+    expect_stdout: "PASS"
+}
+
+issue_4939: {
+    options = {
+        pure_getters: "strict",
+        side_effects: true,
+    }
+    input: {
+        ({
+            __proto__: {
+                get p() {
+                    console.log("PASS");
+                },
+            },
+        }).p;
+    }
+    expect: {
+        ({
+            __proto__: {
+                get p() {
+                    console.log("PASS");
+                },
+            },
+        }).p;
+    }
+    expect_stdout: "PASS"
+}

test/compress/reduce_vars.js

@@ -7631,3 +7631,114 @@ issue_4568: {
     }
     expect_stdout: "PASS"
 }
+
+issue_4937: {
+    options = {
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        function f() {
+            while (console.log("PASS"));
+        }
+        do {
+            function g() {
+                f();
+            }
+        } while (!g);
+        f();
+    }
+    expect: {
+        function f() {
+            while (console.log("PASS"));
+        }
+        do {
+            function g() {
+                f();
+            }
+        } while (!g);
+        f();
+    }
+    expect_stdout: "PASS"
+}
+
+issue_4943_1: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var a, b = 1;
+        (function f() {
+            a = "foo";
+            b-- && f();
+            console.log(a);
+            a = "bar";
+        })();
+    }
+    expect: {
+        var a, b = 1;
+        (function f() {
+            a = "foo";
+            b-- && f();
+            console.log(a);
+            a = "bar";
+        })();
+    }
+    expect_stdout: [
+        "foo",
+        "bar",
+    ]
+}
+
+issue_4943_2: {
+    options = {
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a, b = 1;
+        (function f() {
+            a = "foo";
+            b-- && f();
+            console.log(a);
+            a = "bar";
+        })();
+    }
+    expect: {
+        var a, b = 1;
+        (function f() {
+            a = "foo";
+            b-- && f();
+            console.log(a);
+            a = "bar";
+        })();
+    }
+    expect_stdout: [
+        "foo",
+        "bar",
+    ]
+}
+
+issue_4949: {
+    options = {
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        (function f(a) {
+            a = 0;
+            console.log(a++, arguments[0]);
+        })(0);
+    }
+    expect: {
+        (function(a) {
+            a = 0;
+            console.log(a++, arguments[0]);
+        })(0);
+    }
+    expect_stdout: "0 1"
+}

test/compress/sandbox.js

@@ -172,3 +172,32 @@ issue_4054: {
     }
     expect_stdout: "{ p: [Setter] }"
 }
+
+issue_4811_1: {
+    input: {
+        for (var PASS in this);
+        console.log(PASS, this, {} < this);
+    }
+    expect: {
+        for (var PASS in this);
+        console.log(PASS, this, {} < this);
+    }
+    expect_stdout: "PASS [object global] true"
+}
+
+issue_4811_2: {
+    options = {
+        side_effects: true,
+    }
+    input: {
+        (async function() {});
+        for (var PASS in this);
+        console.log(PASS, this, {} < this);
+    }
+    expect: {
+        for (var PASS in this);
+        console.log(PASS, this, {} < this);
+    }
+    expect_stdout: "PASS [object global] true"
+    node_version: ">=8"
+}

test/compress/sequences.js

@@ -564,6 +564,34 @@ delete_seq_3: {
 }
 
 delete_seq_4: {
+    options = {
+        booleans: true,
+        evaluate: false,
+        sequences: true,
+        side_effects: true,
+    }
+    input: {
+        function f() {}
+        console.log(delete (f(), undefined));
+        console.log(delete (f(), void 0));
+        console.log(delete (f(), Infinity));
+        console.log(delete (f(), 1 / 0));
+        console.log(delete (f(), NaN));
+        console.log(delete (f(), 0 / 0));
+    }
+    expect: {
+        function f() {}
+        console.log(delete void f()),
+        console.log(delete void f()),
+        console.log((f(), delete (1 / 0))),
+        console.log((f(), delete (1 / 0))),
+        console.log(delete (f(), NaN)),
+        console.log((f(), delete(0 / 0)));
+    }
+    expect_stdout: true
+}
+
+delete_seq_4_evaluate: {
     options = {
         booleans: true,
         evaluate: true,
@@ -592,6 +620,35 @@ delete_seq_4: {
 }
 
 delete_seq_5: {
+    options = {
+        booleans: true,
+        evaluate: false,
+        keep_infinity: true,
+        sequences: true,
+        side_effects: true,
+    }
+    input: {
+        function f() {}
+        console.log(delete (f(), undefined));
+        console.log(delete (f(), void 0));
+        console.log(delete (f(), Infinity));
+        console.log(delete (f(), 1 / 0));
+        console.log(delete (f(), NaN));
+        console.log(delete (f(), 0 / 0));
+    }
+    expect: {
+        function f() {}
+        console.log(delete void f()),
+        console.log(delete void f()),
+        console.log(delete (f(), Infinity)),
+        console.log((f(), delete (1 / 0))),
+        console.log(delete (f(), NaN)),
+        console.log((f(), delete (0 / 0)));
+    }
+    expect_stdout: true
+}
+
+delete_seq_5_evaluate: {
     options = {
         booleans: true,
         evaluate: true,
@@ -663,12 +720,21 @@ side_effects_cascade_1: {
             if (a < 0) a = 0;
             b.a = a;
         }
+        var m = {}, n = {};
+        f(13, m);
+        f("foo", n);
+        console.log(m.a, n.a);
     }
     expect: {
         function f(a, b) {
-            (a -= 42) < 0 && (a = 0), b.a = a;
+            b.a = a = (a -= 42) < 0 ? 0 : a;
         }
+        var m = {}, n = {};
+        f(13, m),
+        f("foo", n),
+        console.log(m.a, n.a);
     }
+    expect_stdout: "0 NaN"
 }
 
 side_effects_cascade_2: {

test/compress/side_effects.js

@@ -198,6 +198,36 @@ global_fns: {
     ]
 }
 
+global_constructors: {
+    options = {
+        side_effects: true,
+        unsafe: true,
+    }
+    input: {
+        Map;
+        new Map(console.log("foo"));
+        Set;
+        new Set(console.log("bar"));
+        WeakMap;
+        new WeakMap(console.log("baz"));
+        WeakSet;
+        new WeakSet(console.log("moo"));
+    }
+    expect: {
+        console.log("foo");
+        console.log("bar");
+        console.log("baz");
+        console.log("moo");
+    }
+    expect_stdout: [
+        "foo",
+        "bar",
+        "baz",
+        "moo",
+    ]
+    node_version: ">=0.12"
+}
+
 unsafe_builtin_1: {
     options = {
         side_effects: true,
@@ -558,3 +588,60 @@ drop_side_effect_free_call: {
     }
     expect_stdout: "PASS"
 }
+
+issue_4730_1: {
+    options = {
+        pure_getters: "strict",
+        side_effects: true,
+    }
+    input: {
+        var a;
+        console.log("PASS") + (a && a[a.p]);
+    }
+    expect: {
+        var a;
+        console.log("PASS"),
+        a && a[a.p];
+    }
+    expect_stdout: "PASS"
+}
+
+issue_4730_2: {
+    options = {
+        pure_getters: "strict",
+        side_effects: true,
+    }
+    input: {
+        var a;
+        !console.log("PASS") || a && a[a.p];
+    }
+    expect: {
+        var a;
+        !console.log("PASS") || a && a[a.p];
+    }
+    expect_stdout: "PASS"
+}
+
+issue_4751: {
+    options = {
+        pure_getters: "strict",
+        side_effects: true,
+    }
+    input: {
+        var o = {
+            get p() {
+                console.log("PASS");
+            },
+        };
+        o && o.p;
+    }
+    expect: {
+        var o = {
+            get p() {
+                console.log("PASS");
+            },
+        };
+        o && o.p;
+    }
+    expect_stdout: "PASS"
+}

test/compress/spreads.js

@@ -85,7 +85,7 @@ collapse_vars_4: {
     node_version: ">=6"
 }
 
-conditionals_farg: {
+conditionals_farg_1: {
     options = {
         conditionals: true,
     }
@@ -107,6 +107,28 @@ conditionals_farg: {
     node_version: ">=6"
 }
 
+conditionals_farg_2: {
+    options = {
+        conditionals: true,
+        pure_getters: "strict",
+        reduce_vars: true,
+    }
+    input: {
+        var log = console.log;
+        (function(a) {
+            return a.length ? log(...a) : log("FAIL");
+        })([ "PASS" ]);
+    }
+    expect: {
+        var log = console.log;
+        (function(a) {
+            return a.length ? log(...a) : log("FAIL");
+        })([ "PASS" ]);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
 dont_inline: {
     options = {
         inline: true,
@@ -272,6 +294,31 @@ reduce_vars_2: {
     node_version: ">=6"
 }
 
+reduce_vars_3: {
+    options = {
+        reduce_funcs: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        function f() {}
+        function g() {
+            return (a => a)(...[ f ]);
+        }
+        console.log(g() === g() ? "PASS" : "FAIL");
+    }
+    expect: {
+        function f() {}
+        function g() {
+            return (a => a)(...[ f ]);
+        }
+        console.log(g() === g() ? "PASS" : "FAIL");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
 convert_setter: {
     options = {
         objects: true,
@@ -667,6 +714,57 @@ unused_var_side_effects: {
     node_version: ">=8"
 }
 
+unsafe_join_1: {
+    options = {
+        unsafe: true,
+    }
+    input: {
+        console.log([ ..."foo" ].join());
+    }
+    expect: {
+        console.log([ ..."foo" ].join());
+    }
+    expect_stdout: "f,o,o"
+    node_version: ">=6"
+}
+
+unsafe_join_2: {
+    options = {
+        evaluate: true,
+        unsafe: true,
+    }
+    input: {
+        console.log([ "foo", ..."bar" ].join(""));
+    }
+    expect: {
+        console.log([ "foo", ..."bar" ].join(""));
+    }
+    expect_stdout: "foobar"
+    node_version: ">=6"
+}
+
+unsafe_join_3: {
+    options = {
+        unsafe: true,
+    }
+    input: {
+        try {
+            [].join(...console);
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect: {
+        try {
+            [].join(...console);
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
 issue_4329: {
     options = {
         objects: true,
@@ -947,3 +1045,114 @@ issue_4614: {
     expect_stdout: true
     node_version: ">=6"
 }
+
+issue_4849: {
+    options = {
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        while (function() {
+            while (!console);
+        }(new function(a) {
+            console.log(typeof { ...a });
+        }(function() {})));
+    }
+    expect: {
+        while (function() {
+            while (!console);
+        }(function(a) {
+            console.log(typeof { ...function() {} });
+        }()));
+    }
+    expect_stdout: "object"
+    node_version: ">=8"
+}
+
+issue_4882_1: {
+    options = {
+        objects: true,
+        spreads: true,
+    }
+    input: {
+        var o = {
+            p: "PASS",
+            ... {
+                __proto__: {
+                    p: "FAIL 1",
+                    q: "FAIL 2",
+                },
+            },
+        };
+        console.log(o.p);
+        console.log(o.q);
+    }
+    expect: {
+        var o = {
+            p: "PASS",
+        };
+        console.log(o.p);
+        console.log(o.q);
+    }
+    expect_stdout: [
+        "PASS",
+        "undefined",
+    ]
+    node_version: ">=8"
+}
+
+issue_4882_2: {
+    options = {
+        objects: true,
+        spreads: true,
+    }
+    input: {
+        console.log(null == Object.getPrototypeOf({
+            ... {
+                __proto__: (console.log(42), null),
+            },
+        }) ? "FAIL" : "PASS");
+    }
+    expect: {
+        console.log(null == Object.getPrototypeOf({
+            ... {
+                __proto__: (console.log(42), null),
+            },
+        }) ? "FAIL" : "PASS");
+    }
+    expect_stdout: [
+        "42",
+        "PASS",
+    ]
+    node_version: ">=8"
+}
+
+issue_4882_3: {
+    options = {
+        objects: true,
+        spreads: true,
+    }
+    input: {
+        var o = {
+            __proto__: { p: 42 },
+            ... {
+                set __proto__(v) {},
+            },
+        };
+        console.log(o.__proto__ === Object.getPrototypeOf(o) ? "FAIL" : "PASS");
+        console.log(o.p);
+    }
+    expect: {
+        var o = {
+            __proto__: { p: 42 },
+            ["__proto__"]: void 0,
+        };
+        console.log(o.__proto__ === Object.getPrototypeOf(o) ? "FAIL" : "PASS");
+        console.log(o.p);
+    }
+    expect_stdout: [
+        "PASS",
+        "42",
+    ]
+    node_version: ">=8"
+}

test/compress/templates.js

@@ -62,6 +62,23 @@ tag_parentheses_arrow: {
     node_version: ">=4"
 }
 
+tag_parentheses_binary: {
+    options = {
+        collapse_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var f = function() {
+            console.log("PASS");
+        } || console
+        f``;
+    }
+    expect_exact: '(function(){console.log("PASS")}||console)``;'
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
 tag_parentheses_new: {
     input: {
         (new function() {
@@ -73,6 +90,35 @@ tag_parentheses_new: {
     node_version: ">=4"
 }
 
+tag_parentheses_sequence: {
+    input: {
+        var o = {
+            f() {
+                console.log(this === o ? "FAIL" : "PASS");
+            },
+        };
+        (42, o.f)``;
+    }
+    expect_exact: 'var o={f(){console.log(this===o?"FAIL":"PASS")}};(42,o.f)``;'
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
+tag_parentheses_unary: {
+    input: {
+        var a;
+        try {
+            (~a)``;
+            (a++)``;
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect_exact: 'var a;try{(~a)``;(a++)``}catch(e){console.log("PASS")}'
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
 malformed_escape: {
     input: {
         (function(s) {
@@ -211,7 +257,7 @@ unsafe_evaluate: {
     node_version: ">=8"
 }
 
-side_effects: {
+side_effects_1: {
     options = {
         side_effects: true,
     }
@@ -228,6 +274,30 @@ side_effects: {
     node_version: ">=4"
 }
 
+side_effects_2: {
+    options = {
+        side_effects: true,
+    }
+    input: {
+        var o = {
+            f() {
+                console.log(this === o ? "FAIL" : "PASS");
+            },
+        };
+        (42, o.f)``;
+    }
+    expect: {
+        var o = {
+            f() {
+                console.log(this === o ? "FAIL" : "PASS");
+            },
+        };
+        (0, o.f)``;
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
 unsafe_side_effects: {
     options = {
         side_effects: true,
@@ -245,6 +315,21 @@ unsafe_side_effects: {
     node_version: ">=4"
 }
 
+pure_funcs: {
+    options = {
+        pure_funcs: "Math.random",
+        side_effects: true,
+    }
+    input: {
+        Math.random`${console.log("PASS")}`;
+    }
+    expect: {
+        console.log("PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
 issue_4604: {
     options = {
         collapse_vars: true,
@@ -305,7 +390,7 @@ issue_4676: {
         reduce_vars: true,
         templates: true,
         toplevel: true,
-        unsafe:true,
+        unsafe: true,
         unused: true,
     }
     input: {
@@ -328,3 +413,24 @@ issue_4676: {
     expect_stdout: "PASS"
     node_version: ">=4"
 }
+
+issue_4931: {
+    options = {
+        evaluate: true,
+        templates: true,
+        unsafe: true,
+    }
+    input: {
+        console.log(String.raw`${typeof A} ${"\r"}`);
+        console.log(String.raw`${"\\"} ${"`"}`);
+    }
+    expect: {
+        console.log(String.raw`${typeof A} ${"\r"}`);
+        console.log("\\ `");
+    }
+    expect_stdout: [
+        "undefined \r",
+        "\\ `",
+    ]
+    node_version: ">=4"
+}

test/compress/unicode.js

@@ -50,7 +50,7 @@ unicode_parse_variables: {
     }
 }
 
-unicode_escaped_identifier: {
+unicode_escaped_identifier_1: {
     input: {
         var \u0061 = "\ud800\udc00";
         console.log(a);
@@ -59,6 +59,17 @@ unicode_escaped_identifier: {
     expect_stdout: "\ud800\udc00"
 }
 
+unicode_escaped_identifier_2: {
+    input: {
+        var \u{61} = "foo";
+        var \u{10000} = "bar";
+        console.log(a, \u{10000});
+    }
+    expect_exact: 'var a="foo";var \u{10000}="bar";console.log(a,\u{10000});'
+    expect_stdout: "foo bar"
+    node_version: ">=4"
+}
+
 unicode_identifier_ascii_only: {
     beautify = {
         ascii_only: true,

test/compress/varify.js

@@ -354,6 +354,92 @@ forin_let_2: {
     node_version: ">=6"
 }
 
+loop_scope_1: {
+    options = {
+        toplevel: true,
+        varify: true,
+    }
+    input: {
+        "use strict";
+        var o = { foo: 1, bar: 2 };
+        for (let i in o) {
+            console.log(i);
+        }
+        for (const j in o)
+            setTimeout(() => console.log(j), 0);
+        for (let k in o)
+            setTimeout(function() {
+                console.log(k);
+            }, 0);
+    }
+    expect: {
+        "use strict";
+        var o = { foo: 1, bar: 2 };
+        for (var i in o)
+            console.log(i);
+        for (const j in o)
+            setTimeout(() => console.log(j), 0);
+        for (let k in o)
+            setTimeout(function() {
+                console.log(k);
+            }, 0);
+    }
+    expect_stdout: [
+        "foo",
+        "bar",
+        "foo",
+        "bar",
+        "foo",
+        "bar",
+    ]
+    node_version: ">=4"
+}
+
+loop_scope_2: {
+    options = {
+        reduce_vars: true,
+        toplevel: true,
+        varify: true,
+    }
+    input: {
+        "use strict";
+        var a = [ "foo", "bar" ];
+        for (var i = 0; i < a.length; i++) {
+            const x = a[i];
+            console.log(x);
+            let y = a[i];
+            setTimeout(() => console.log(y), 0);
+            const z = a[i];
+            setTimeout(function() {
+                console.log(z);
+            }, 0);
+        }
+    }
+    expect: {
+        "use strict";
+        var a = [ "foo", "bar" ];
+        for (var i = 0; i < a.length; i++) {
+            var x = a[i];
+            console.log(x);
+            let y = a[i];
+            setTimeout(() => console.log(y), 0);
+            const z = a[i];
+            setTimeout(function() {
+                console.log(z);
+            }, 0);
+        }
+    }
+    expect_stdout: [
+        "foo",
+        "bar",
+        "foo",
+        "foo",
+        "bar",
+        "bar",
+    ]
+    node_version: ">=4"
+}
+
 issue_4290_1_const: {
     options = {
         reduce_vars: true,
@@ -409,3 +495,121 @@ drop_forin_let: {
     expect_stdout: "PASS"
     node_version: ">=4"
 }
+
+default_init: {
+    options = {
+        join_vars: true,
+        reduce_vars: true,
+        unused: true,
+        varify: true,
+    }
+    input: {
+        A = "PASS";
+        (function() {
+            "use strict";
+            let a;
+            a = A;
+            console.log(a);
+        })();
+    }
+    expect: {
+        A = "PASS";
+        (function() {
+            "use strict";
+            var a = A;
+            console.log(a);
+        })();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
+issue_4933_1: {
+    options = {
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+        varify: true,
+    }
+    input: {
+        console.log(f());
+        function f() {
+            var a;
+            for (console in a = [ f ]) {
+                const b = a;
+            }
+        }
+    }
+    expect: {
+        console.log(function f() {
+            var a;
+            for (console in a = [ f ]) {
+                const b = a;
+            }
+        }());
+    }
+    expect_stdout: "undefined"
+}
+
+issue_4933_2: {
+    options = {
+        passes: 2,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+        varify: true,
+    }
+    input: {
+        console.log(f());
+        function f() {
+            var a;
+            for (console in a = [ f ]) {
+                const b = a;
+            }
+        }
+    }
+    expect: {
+        console.log(function f() {
+            for (console in [ f ]);
+        }());
+    }
+    expect_stdout: "undefined"
+}
+
+issue_4954: {
+    options = {
+        functions: true,
+        reduce_vars: true,
+        unused: true,
+        varify: true,
+    }
+    input: {
+        "use strict";
+        (function() {
+            {
+                let a = console;
+                console.log(typeof a);
+            }
+            {
+                let a = function() {};
+                a && console.log(typeof a);
+            }
+        })();
+    }
+    expect: {
+        "use strict";
+        (function() {
+            var a = console;
+            console.log(typeof a);
+            {
+                let a = function() {};
+                a && console.log(typeof a);
+            }
+        })();
+    }
+    expect_stdout: [
+        "object",
+        "function",
+    ]
+    node_version: ">=4"
+}

test/compress/yields.js

@@ -150,6 +150,27 @@ for_await_of: {
     node_version: ">=10"
 }
 
+comment_newline: {
+    beautify = {
+        comments: "all",
+    }
+    input: {
+        console.log(function*() {
+            yield (
+                /* */
+                "PASS"
+            );
+        }().next().value);
+    }
+    expect_exact: [
+        "console.log(function*(){",
+        "/* */",
+        'yield"PASS"}().next().value);',
+    ]
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
 collapse_vars_1: {
     options = {
         collapse_vars: true,
@@ -247,6 +268,30 @@ collapse_vars_4: {
     node_version: ">=4"
 }
 
+collapse_vars_5: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        var a = function* f(b, c) {
+            b = yield c = b;
+            console.log(c);
+        }("PASS");
+        a.next();
+        a.next("FAIL");
+    }
+    expect: {
+        var a = function* f(b, c) {
+            b = yield c = b;
+            console.log(c);
+        }("PASS");
+        a.next();
+        a.next("FAIL");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
 collapse_property_lambda: {
     options = {
         collapse_vars: true,
@@ -388,14 +433,14 @@ functions: {
             function* b() {
                 return !!b;
             }
-            var c = function*(c) {
+            function* c(c) {
                 return c;
-            };
-            if (yield* c(yield* b(yield* a()))) {
-                function* d() {}
-                function* e() {
-                    return typeof e;
             }
+            if (yield* c(yield* b(yield* a()))) {
+                var d = function*() {};
+                var e = function* y() {
+                    return typeof y;
+                };
                 var f = function*(f) {
                     return f;
                 };
@@ -446,9 +491,9 @@ functions_use_strict: {
             function* b() {
                 return !!b;
             }
-            var c = function*(c) {
+            function* c(c) {
                 return c;
-            };
+            }
             if (yield* c(yield* b(yield* a()))) {
                 var d = function*() {};
                 var e = function* y() {
@@ -465,6 +510,54 @@ functions_use_strict: {
     node_version: ">=4"
 }
 
+functions_anonymous: {
+    options = {
+        functions: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var yield = function*() {
+            return "PASS";
+        };
+        console.log(yield().next(yield).value);
+    }
+    expect: {
+        function* yield() {
+            return "PASS";
+        }
+        console.log(yield().next(yield).value);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
+functions_inner_var: {
+    options = {
+        functions: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var yield = function* a() {
+            var a;
+            console.log(a, a);
+        };
+        yield().next(yield);
+    }
+    expect: {
+        function* yield() {
+            var a;
+            console.log(a, a);
+        }
+        yield().next(yield);
+    }
+    expect_stdout: "undefined undefined"
+    node_version: ">=4"
+}
+
 negate_iife: {
     options = {
         negate_iife: true,
@@ -950,3 +1043,43 @@ issue_4641_2: {
     ]
     node_version: ">=10"
 }
+
+issue_4769_1: {
+    options = {
+        side_effects: true,
+    }
+    input: {
+        console.log(function*() {
+            (function({} = yield => {}) {})();
+        }().next().done);
+    }
+    expect: {
+        console.log(function*() {
+            (function({} = yield => {}) {})();
+        }().next().done);
+    }
+    expect_stdout: "true"
+    node_version: ">=6"
+}
+
+issue_4769_2: {
+    options = {
+        inline: true,
+    }
+    input: {
+        console.log(function*() {
+            return function({} = yield => {}) {
+                return "PASS";
+            }();
+        }().next().value);
+    }
+    expect: {
+        console.log(function*() {
+            return function({} = yield => {}) {
+                return "PASS";
+            }();
+        }().next().value);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}

test/input/invalid/assign_4.js

@@ -1 +1 @@
-++null
+console.log(4 || (null = 4));

test/input/invalid/assign_5.js

@@ -0,0 +1 @@
+console.log(5 || ([]?.length ^= 5));

test/input/invalid/for-await.js

@@ -0,0 +1 @@
+for await (; console.log(42););

test/jetstream.js

@@ -58,22 +58,29 @@ if (typeof phantom == "undefined") {
     }).listen();
     server.on("listening", function() {
         var port = server.address().port;
-        if (debug) {
+        if (debug) return console.log("http://localhost:" + port + "/");
-            console.log("http://localhost:" + port + "/");
+        var cmd = process.platform == "win32" ? "npm.cmd" : "npm";
-        } else (function install() {
+
-            child_process.spawn(process.platform == "win32" ? "npm.cmd" : "npm", [
+        function npm(args, done) {
+            child_process.spawn(cmd, args, { stdio: [ "ignore", 1, 2 ] }).on("exit", done);
+        }
+
+        (function install() {
+            npm([
                 "install",
                 "phantomjs-prebuilt@2.1.14",
                 "--no-audit",
                 "--no-optional",
                 "--no-save",
                 "--no-update-notifier",
-            ], {
+            ], function(code) {
-                stdio: [ "ignore", 1, 2 ]
-            }).on("exit", function(code) {
                 if (code) {
                     console.log("npm install failed with code", code);
-                    return install();
+                    return npm([
+                        "cache",
+                        "clean",
+                        "--force",
+                    ], install);
                 }
                 var program = require("phantomjs-prebuilt").exec(process.argv[1], port);
                 program.stdout.pipe(process.stdout);

test/mocha/cli.js

@@ -29,7 +29,7 @@ describe("bin/uglifyjs", function() {
         var command = uglifyjscmd + ' test/input/comments/filter.js --comments all';
         exec(command, function(err, stdout) {
             if (err) throw err;
-            assert.strictEqual(stdout, "// foo\n/*@preserve*/\n// bar\n\n");
+            assert.strictEqual(stdout, "// foo\n/*@preserve*/\n// bar\n");
             done();
         });
     });
@@ -37,7 +37,7 @@ describe("bin/uglifyjs", function() {
         var command = uglifyjscmd + ' test/input/comments/filter.js --comments /r/';
         exec(command, function(err, stdout) {
             if (err) throw err;
-            assert.strictEqual(stdout, "/*@preserve*/\n// bar\n\n");
+            assert.strictEqual(stdout, "/*@preserve*/\n// bar\n");
             done();
         });
     });
@@ -45,7 +45,7 @@ describe("bin/uglifyjs", function() {
         var command = uglifyjscmd + ' test/input/comments/filter.js --comments';
         exec(command, function(err, stdout) {
             if (err) throw err;
-            assert.strictEqual(stdout, "/*@preserve*/\n\n");
+            assert.strictEqual(stdout, "/*@preserve*/\n");
             done();
         });
     });
@@ -427,16 +427,30 @@ describe("bin/uglifyjs", function() {
             done();
         });
     });
-    it("Should throw syntax error (++null)", function(done) {
+    it("Should throw syntax error (null = 4)", function(done) {
         var command = uglifyjscmd + " test/input/invalid/assign_4.js";
         exec(command, function(err, stdout, stderr) {
             assert.ok(err);
             assert.strictEqual(stdout, "");
             assert.strictEqual(stderr.split(/\n/).slice(0, 4).join("\n"), [
-                "Parse error at test/input/invalid/assign_4.js:1,0",
+                "Parse error at test/input/invalid/assign_4.js:1,23",
-                "++null",
+                "console.log(4 || (null = 4));",
-                "^",
+                "                       ^",
-                "ERROR: Invalid use of ++ operator",
+                "ERROR: Invalid assignment",
+            ].join("\n"));
+            done();
+        });
+    });
+    it("Should throw syntax error ([]?.length ^= 5)", function(done) {
+        var command = uglifyjscmd + " test/input/invalid/assign_5.js";
+        exec(command, function(err, stdout, stderr) {
+            assert.ok(err);
+            assert.strictEqual(stdout, "");
+            assert.strictEqual(stderr.split(/\n/).slice(0, 4).join("\n"), [
+                "Parse error at test/input/invalid/assign_5.js:1,29",
+                "console.log(5 || ([]?.length ^= 5));",
+                "                             ^",
+                "ERROR: Invalid assignment",
             ].join("\n"));
             done();
         });
@@ -679,6 +693,20 @@ describe("bin/uglifyjs", function() {
             done();
         });
     });
+    it("Should throw syntax error (for-await)", function(done) {
+        var command = uglifyjscmd + " test/input/invalid/for-await.js";
+        exec(command, function(err, stdout, stderr) {
+            assert.ok(err);
+            assert.strictEqual(stdout, "");
+            assert.strictEqual(stderr.split(/\n/).slice(0, 4).join("\n"), [
+                "Parse error at test/input/invalid/for-await.js:1,11",
+                "for await (; console.log(42););",
+                "           ^",
+                "ERROR: Unexpected token: punc «;»",
+            ].join("\n"));
+            done();
+        });
+    });
     it("Should throw syntax error (switch defaults)", function(done) {
         var command = uglifyjscmd + " test/input/invalid/switch.js";
         exec(command, function(err, stdout, stderr) {

test/mocha/comments.js

@@ -392,12 +392,12 @@ describe("comments", function() {
     describe("comment filters", function() {
         it("Should be able to filter comments by passing regexp", function() {
             var ast = UglifyJS.parse("/*!test1*/\n/*test2*/\n//!test3\n//test4\n<!--test5\n<!--!test6\n-->test7\n-->!test8");
-            assert.strictEqual(ast.print_to_string({comments: /^!/}), "/*!test1*/\n//!test3\n//!test6\n//!test8\n");
+            assert.strictEqual(ast.print_to_string({comments: /^!/}), "/*!test1*/\n//!test3\n//!test6\n//!test8");
         });
 
         it("Should be able to filter comments with the 'all' option", function() {
             var ast = UglifyJS.parse("/*!test1*/\n/*test2*/\n//!test3\n//test4\n<!--test5\n<!--!test6\n-->test7\n-->!test8");
-            assert.strictEqual(ast.print_to_string({comments: "all"}), "/*!test1*/\n/*test2*/\n//!test3\n//test4\n//test5\n//!test6\n//test7\n//!test8\n");
+            assert.strictEqual(ast.print_to_string({comments: "all"}), "/*!test1*/\n/*test2*/\n//!test3\n//test4\n//test5\n//!test6\n//test7\n//!test8");
         });
 
         it("Should be able to filter commments with the 'some' option", function() {
@@ -410,13 +410,12 @@ describe("comments", function() {
             var f = function(node, comment) {
                 return comment.value.length === 8;
             };
-
+            assert.strictEqual(ast.print_to_string({comments: f}), "/*TEST 123*/\n//8 chars.");
-            assert.strictEqual(ast.print_to_string({comments: f}), "/*TEST 123*/\n//8 chars.\n");
         });
 
         it("Should be able to filter comments by passing regex in string format", function() {
             var ast = UglifyJS.parse("/*!test1*/\n/*test2*/\n//!test3\n//test4\n<!--test5\n<!--!test6\n-->test7\n-->!test8");
-            assert.strictEqual(ast.print_to_string({comments: "/^!/"}), "/*!test1*/\n//!test3\n//!test6\n//!test8\n");
+            assert.strictEqual(ast.print_to_string({comments: "/^!/"}), "/*!test1*/\n//!test3\n//!test6\n//!test8");
         });
 
         it("Should be able to get the comment and comment type when using a function", function() {
@@ -424,14 +423,12 @@ describe("comments", function() {
             var f = function(node, comment) {
                 return comment.type == "comment1" || comment.type == "comment3";
             };
-
+            assert.strictEqual(ast.print_to_string({comments: f}), "//!test3\n//test4\n//test5\n//!test6");
-            assert.strictEqual(ast.print_to_string({comments: f}), "//!test3\n//test4\n//test5\n//!test6\n");
         });
 
         it("Should be able to filter comments by passing a boolean", function() {
             var ast = UglifyJS.parse("/*!test1*/\n/*test2*/\n//!test3\n//test4\n<!--test5\n<!--!test6\n-->test7\n-->!test8");
-
+            assert.strictEqual(ast.print_to_string({comments: true}), "/*!test1*/\n/*test2*/\n//!test3\n//test4\n//test5\n//!test6\n//test7\n//!test8");
-            assert.strictEqual(ast.print_to_string({comments: true}), "/*!test1*/\n/*test2*/\n//!test3\n//test4\n//test5\n//!test6\n//test7\n//!test8\n");
             assert.strictEqual(ast.print_to_string({comments: false}), "");
         });
 
@@ -439,10 +436,8 @@ describe("comments", function() {
             var ast = UglifyJS.parse("#!Random comment\n//test1\n/*test2*/");
             var f = function(node, comment) {
                 assert.strictEqual(comment.type === "comment5", false);
-
                 return true;
             };
-
             assert.strictEqual(ast.print_to_string({comments: f}), "#!Random comment\n//test1\n/*test2*/");
         });
 
@@ -453,9 +448,8 @@ describe("comments", function() {
 
         it("Should have no problem on multiple calls", function() {
             const options = {
-                comments: /ok/
+                comments: /ok/,
             };
-
             assert.strictEqual(UglifyJS.parse("/* ok */ function a(){}").print_to_string(options), "/* ok */function a(){}");
             assert.strictEqual(UglifyJS.parse("/* ok */ function a(){}").print_to_string(options), "/* ok */function a(){}");
             assert.strictEqual(UglifyJS.parse("/* ok */ function a(){}").print_to_string(options), "/* ok */function a(){}");
@@ -463,14 +457,14 @@ describe("comments", function() {
 
         it("Should handle shebang and preamble correctly", function() {
             var code = UglifyJS.minify("#!/usr/bin/node\nvar x = 10;", {
-                output: { preamble: "/* Build */" }
+                output: { preamble: "/* Build */" },
             }).code;
             assert.strictEqual(code, "#!/usr/bin/node\n/* Build */\nvar x=10;");
         });
 
         it("Should handle preamble without shebang correctly", function() {
             var code = UglifyJS.minify("var x = 10;", {
-                output: { preamble: "/* Build */" }
+                output: { preamble: "/* Build */" },
             }).code;
             assert.strictEqual(code, "/* Build */\nvar x=10;");
         });

test/mocha/let.js

@@ -7,11 +7,11 @@ describe("let", function() {
         // Produce a lot of variables in a function and run it through mangle.
         var s = '"dddddeeeeelllllooooottttt"; function foo() {';
         for (var i = 0; i < 18000; i++) {
-            s += "var v" + i + "=0;";
+            s += "var v" + i + "=[];";
         }
         s += '}';
         var result = UglifyJS.minify(s, {
-            compress: false
+            compress: false,
         }).code;
 
         // Verify that select keywords and reserved keywords not produced

test/mocha/minify.js

@@ -235,8 +235,8 @@ describe("minify", function() {
                 }
             });
             var code = result.code;
-            assert.strictEqual(code, "var a=/* */function(){foo()}();");
+            assert.strictEqual(code, "var a=function(){foo()}();");
-        })
+        });
     });
 
     describe("JS_Parse_Error", function() {

test/mocha/reduce.js

@@ -183,6 +183,24 @@ describe("test/reduce.js", function() {
             "// }",
         ].join("\n"));
     });
+    it("Should reduce `for (const ... in ...)` without invalid intermediate AST", function() {
+        if (semver.satisfies(process.version, "<4")) return;
+        var code = [
+            "var a = 0;",
+            "",
+            "for (const b in [ 1, 2, 3 ]) {",
+            "    a = +a + 1 - .2;",
+            "    console.log(a);",
+            "}",
+        ].join("\n");
+        var result = reduce_test(code, {
+            compress: {
+                unsafe_math: true,
+            },
+        });
+        if (result.error) throw result.error;
+        assert.deepEqual(result.warnings, []);
+    });
     it("Should reduce infinite loops with reasonable performance", function() {
         if (semver.satisfies(process.version, "<=0.10")) return;
         this.timeout(120000);
@@ -361,4 +379,39 @@ describe("test/reduce.js", function() {
         if (result.error) throw result.error;
         assert.strictEqual(result.code, read("test/input/reduce/destructured_catch.reduced.js"));
     });
+    it("Should not enumerate `toString` over global context", function() {
+        if (semver.satisfies(process.version, "<8")) return;
+        var code = [
+            "(async function() {});",
+            "for (var k in this);",
+            "console.log(k, 42 + this);",
+        ].join("\n");
+        var result = reduce_test(code, {
+            mangle: false,
+        });
+        if (result.error) throw result.error;
+        assert.strictEqual(result.code, [
+            "// Can't reproduce test failure",
+            "// minify options: {",
+            '//   "mangle": false',
+            "// }",
+        ].join("\n"));
+    });
+    it("Should reduce object with method syntax without invalid intermediate AST", function() {
+        if (semver.satisfies(process.version, "<4")) return;
+        var code = [
+            "console.log({",
+            "    f() {",
+            "        return 1 - .8;",
+            "    },",
+            "}.f());",
+        ].join("\n");
+        var result = reduce_test(code, {
+            compress: {
+                unsafe_math: true,
+            },
+        });
+        if (result.error) throw result.error;
+        assert.deepEqual(result.warnings, []);
+    });
 });

test/mocha/sourcemaps.js

@@ -101,6 +101,19 @@ describe("sourcemaps", function() {
         var map = JSON.parse(result.map);
         assert.deepEqual(map.names, []);
     });
+    it("Should mark class properties", function() {
+        var result = UglifyJS.minify([
+            "class A {",
+            "    static P = 42",
+            "    set #q(v) {}",
+            "}",
+        ].join("\n"), {
+            sourceMap: true,
+        });
+        if (result.error) throw result.error;
+        assert.strictEqual(result.code, "class A{static P=42;set#q(s){}}");
+        assert.strictEqual(result.map, '{"version":3,"sources":["0"],"names":["A","P","#q","v"],"mappings":"MAAMA,EACFC,SAAW,GACXC,MAAOC"}');
+    });
     it("Should mark array/object literals", function() {
         var result = UglifyJS.minify([
             "var obj = {};",

test/mozilla-ast.js

@@ -5,23 +5,23 @@ var acorn = require("acorn");
 var ufuzz = require("./ufuzz");
 var UglifyJS = require("..");
 
-function try_beautify(code) {
+function beautify(ast) {
-    var beautified = UglifyJS.minify(code, {
+    var beautified = UglifyJS.minify(ast, {
         compress: false,
         mangle: false,
         output: {
             beautify: true,
-            braces: true
+            braces: true,
-        }
+        },
+    });
+    if (beautified.error) return beautified;
+    return UglifyJS.minify(beautified.code, {
+        compress: false,
+        mangle: false,
+        output: {
+            ast: true,
+        },
     });
-    if (beautified.error) {
-        console.log("// !!! beautify failed !!!");
-        console.log(beautified.error.stack);
-        console.log(code);
-    } else {
-        console.log("// (beautified)");
-        console.log(beautified.code);
-    }
 }
 
 function validate(ast) {
@@ -35,16 +35,55 @@ function validate(ast) {
     return UglifyJS.minify(ast, {
         compress: false,
         mangle: false,
+        output: {
+            ast: true,
+        },
+        validate: true,
     });
 }
 
-function test(original, estree, description) {
+function patch_import(code) {
-    var transformed = validate(UglifyJS.AST_Node.from_mozilla_ast(estree));
+    return code.replace(/\bimport\s*\{\s*\}\s*from\s*(['"])/g, "import$1")
-    if (transformed.error || original !== transformed.code) {
+        .replace(/\b(import\b.*?)\s*,\s*\{\s*\}\s*(from\s*['"])/g, "$1 $2");
+}
+
+function equals(input, transformed) {
+    if (input.code === transformed.code) return true;
+    return patch_import(input.code) === patch_import(transformed.code);
+}
+
+function test(input, to_moz, description, skip_on_error, beautified) {
+    try {
+        var ast = UglifyJS.AST_Node.from_mozilla_ast(to_moz(input));
+    } catch (e) {
+        if (skip_on_error) return true;
+        console.log("//=============================================================");
+        console.log("//", description, "failed... round", round);
+        console.log(e);
+        console.log("// original code");
+        if (beautified === true) console.log("// (beautified)");
+        console.log(input.code);
+        return false;
+    }
+    var transformed = validate(ast);
+    if (transformed.error || !equals(input, transformed)) {
+        if (!beautified) {
+            beautified = beautify(input.ast);
+            if (!beautified.error) {
+                beautified.raw = beautified.code;
+                if (!test(beautified, to_moz, description, skip_on_error, true)) return false;
+            }
+        }
         console.log("//=============================================================");
         console.log("// !!!!!! Failed... round", round);
         console.log("// original code");
-        try_beautify(original);
+        if (beautified.error) {
+            console.log("// !!! beautify failed !!!");
+            console.log(beautified.error.stack);
+        } else if (beautified === true) {
+            console.log("// (beautified)");
+        }
+        console.log(input.raw);
         console.log();
         console.log();
         console.log("//-------------------------------------------------------------");
@@ -52,7 +91,15 @@ function test(original, estree, description) {
         if (transformed.error) {
             console.log(transformed.error.stack);
         } else {
-            try_beautify(transformed.code);
+            beautified = beautify(transformed.ast);
+            if (beautified.error) {
+                console.log("// !!! beautify failed !!!");
+                console.log(beautified.error.stack);
+                console.log(transformed.code);
+            } else {
+                console.log("// (beautified)");
+                console.log(beautified.code);
+            }
         }
         console.log("!!!!!! Failed... round", round);
         return false;
@@ -67,24 +114,33 @@ for (var round = 1; round <= num_iterations; round++) {
     process.stdout.write(round + " of " + num_iterations + "\r");
     var code = ufuzz.createTopLevelCode();
     minify_options.forEach(function(options) {
-        var input = options ? UglifyJS.minify(code, JSON.parse(options)).code : code;
+        var ok = true;
-        var uglified = UglifyJS.minify(input, {
+        var input = UglifyJS.minify(options ? UglifyJS.minify(code, JSON.parse(options)).code : code, {
             compress: false,
             mangle: false,
             output: {
-                ast: true
+                ast: true,
-            }
+            },
         });
-        var ok = test(uglified.code, uglified.ast.to_mozilla_ast(), "AST_Node.to_mozilla_ast()");
+        input.raw = options ? input.code : code;
-        try {
+        if (input.error) {
-            ok = test(uglified.code, acorn.parse(input), "acorn.parse()") && ok;
+            ok = false;
-        } catch (e) {
             console.log("//=============================================================");
-            console.log("// acorn parser failed... round", round);
+            console.log("// minify() failed... round", round);
-            console.log(e);
+            console.log(input.error);
             console.log("// original code");
-            console.log(input);
+            console.log(code);
         }
+        if (ok) ok = test(input, function(input) {
+            return input.ast.to_mozilla_ast();
+        }, "AST_Node.to_mozilla_ast()");
+        if (ok) ok = test(input, function(input) {
+            return acorn.parse(input.raw, {
+                ecmaVersion: "latest",
+                locations: true,
+                sourceType: "module",
+            });
+        }, "acorn.parse()", !ufuzz.verbose);
         if (!ok) process.exit(1);
     });
 }

test/reduce.js

@@ -46,7 +46,7 @@ module.exports = function reduce_test(testcase, minify_options, reduce_options)
     if (verbose) {
         log("// Node.js " + process.version + " on " + os.platform() + " " + os.arch());
     }
-    if (differs.error && [ "DefaultsError", "SyntaxError" ].indexOf(differs.error.name) < 0) {
+    if (differs && differs.error && [ "DefaultsError", "SyntaxError" ].indexOf(differs.error.name) < 0) {
         test_for_diff = test_minify;
         differs = test_for_diff(testcase, minify_options, result_cache, max_timeout);
     }
@@ -132,15 +132,26 @@ module.exports = function reduce_test(testcase, minify_options, reduce_options)
                 return;
             }
             if (parent instanceof U.AST_VarDef && parent.name === node) return;
+            // preserve class methods
+            if (parent instanceof U.AST_ClassMethod && parent.value === node) return;
             // preserve exports
             if (parent instanceof U.AST_ExportDeclaration) return;
             if (parent instanceof U.AST_ExportDefault) return;
             if (parent instanceof U.AST_ExportForeign) return;
             if (parent instanceof U.AST_ExportReferences) return;
+            // preserve sole definition of an export statement
+            if (node instanceof U.AST_VarDef
+                && parent.definitions.length == 1
+                && tt.parent(1) instanceof U.AST_ExportDeclaration) {
+                return;
+            }
             // preserve for (var xxx; ...)
             if (parent instanceof U.AST_For && parent.init === node && node instanceof U.AST_Definitions) return node;
             // preserve for (xxx in/of ...)
             if (parent instanceof U.AST_ForEnumeration && parent.init === node) return node;
+            // preserve super(...)
+            if (node.TYPE == "Call" && node.expression instanceof U.AST_Super) return;
+            if (node instanceof U.AST_Super && parent.TYPE == "Call" && parent.expression === node) return node;
 
             // node specific permutations with no parent logic
 
@@ -202,12 +213,10 @@ module.exports = function reduce_test(testcase, minify_options, reduce_options)
                 }
                 if (node.expression instanceof U.AST_Function) {
                     // hoist and return expressions from the IIFE function expression
-                    var body = node.expression.body;
-                    node.expression.body = [];
                     var seq = [];
-                    body.forEach(function(node) {
+                    node.expression.body.forEach(function(node) {
                         var expr = expr instanceof U.AST_Exit ? node.value : node.body;
-                        if (expr instanceof U.AST_Node && !U.is_statement(expr)) {
+                        if (expr instanceof U.AST_Node && !U.is_statement(expr) && can_hoist(expr)) {
                             // collect expressions from each statements' body
                             seq.push(expr);
                         }
@@ -258,7 +267,7 @@ module.exports = function reduce_test(testcase, minify_options, reduce_options)
                     CHANGED = true;
                     return List.skip;
                   default:
-                    if (!has_exit(node)) {
+                    if (!has_exit(node) && can_hoist(node)) {
                         // hoist function declaration body
                         var body = node.body;
                         node.body = [];
@@ -312,10 +321,11 @@ module.exports = function reduce_test(testcase, minify_options, reduce_options)
                 var expr;
                 switch ((node.start._permute * steps | 0) % 3) {
                   case 0:
-                    if (!(node.init instanceof U.AST_Definitions
+                    if (node.init instanceof U.AST_Definitions) {
-                        && node.init.definitions[0].name instanceof U.AST_Destructured)) {
+                        if (node.init instanceof U.AST_Const) break;
-                        expr = node.init;
+                        if (node.init.definitions[0].name instanceof U.AST_Destructured) break;
                     }
+                    expr = node.init;
                     break;
                   case 1:
                     expr = node.object;
@@ -375,11 +385,9 @@ module.exports = function reduce_test(testcase, minify_options, reduce_options)
                 if (node.body instanceof U.AST_Call && node.body.expression instanceof U.AST_Function) {
                     // hoist simple statement IIFE function expression body
                     node.start._permute++;
-                    if (!has_exit(node.body.expression)) {
+                    if (!has_exit(node.body.expression) && can_hoist(node.body.expression)) {
-                        var body = node.body.expression.body;
-                        node.body.expression.body = [];
                         CHANGED = true;
-                        return List.splice(body);
+                        return List.splice(node.body.expression.body);
                     }
                 }
             }
@@ -460,13 +468,6 @@ module.exports = function reduce_test(testcase, minify_options, reduce_options)
                     return List.skip;
                 }
 
-                // preserve sole definition of an export statement
-                if (node instanceof U.AST_VarDef
-                    && parent.definitions.length == 1
-                    && tt.parent(1) instanceof U.AST_ExportDeclaration) {
-                    return node;
-                }
-
                 // remove this node unless its the sole element of a (transient) sequence
                 if (!(parent instanceof U.AST_Sequence) || parent.expressions.length > 1) {
                     node.start._permute++;
@@ -489,23 +490,27 @@ module.exports = function reduce_test(testcase, minify_options, reduce_options)
             CHANGED = true;
             return newNode;
         }, function(node, in_list) {
-            if (node instanceof U.AST_Sequence) {
+            if (node instanceof U.AST_Definitions) {
+                // remove empty var statement
+                if (node.definitions.length == 0) return in_list ? List.skip : new U.AST_EmptyStatement({
+                    start: {},
+                });
+            } else if (node instanceof U.AST_ObjectMethod) {
+                if (!/Function$/.test(node.value.TYPE)) return new U.AST_ObjectKeyVal({
+                    key: node.key,
+                    value: node.value,
+                    start: {},
+                });
+            } else if (node instanceof U.AST_Sequence) {
                 // expand single-element sequence
                 if (node.expressions.length == 1) return node.expressions[0];
-            }
+            } else if (node instanceof U.AST_Try) {
-            else if (node instanceof U.AST_Try) {
                 // expand orphaned try block
                 if (!node.bcatch && !node.bfinally) return new U.AST_BlockStatement({
                     body: node.body,
                     start: {},
                 });
             }
-            else if (node instanceof U.AST_Definitions) {
-                // remove empty var statement
-                if (node.definitions.length == 0) return in_list ? List.skip : new U.AST_EmptyStatement({
-                    start: {},
-                });
-            }
         });
 
         var diff_error_message;
@@ -674,6 +679,20 @@ function has_loopcontrol(body, loop, label) {
     return found;
 }
 
+function can_hoist(body) {
+    var found = false;
+    body.walk(new U.TreeWalker(function(node) {
+        if (found) return true;
+        if (node instanceof U.AST_NewTarget) return found = true;
+        if (node instanceof U.AST_Scope) {
+            if (node === body) return;
+            return true;
+        }
+        if (node instanceof U.AST_Super) return found = true;
+    }));
+    return !found;
+}
+
 function is_timed_out(result) {
     return sandbox.is_error(result) && /timed out/.test(result.message);
 }

test/release/acorn.sh

@@ -0,0 +1,105 @@
+#!/bin/sh
+
+alias uglify-js=$PWD/bin/uglifyjs
+UGLIFY_OPTIONS=$@
+
+minify_in_situ() {
+    ARGS="$UGLIFY_OPTIONS --validate --in-situ"
+    DIRS="$1"
+    echo '> uglify-js' $DIRS $UGLIFY_OPTIONS
+    for i in `find $DIRS -type f -name '*.js'`
+    do
+        ARGS="$ARGS $i"
+    done
+    uglify-js $ARGS
+}
+
+npm_install() {
+    PKG="$1"
+    while !(npm install $PKG); do
+        while !(npm cache clean --force); do echo "'npm cache clean' failed - retrying..."; done
+    done
+}
+
+rm -rf tmp/acorn \
+&& git clone https://github.com/acornjs/acorn.git tmp/acorn \
+&& cd tmp/acorn \
+&& rm -rf .git/hooks \
+&& git checkout 74b59384320ced82e09da2e8fdbed16810f7379a \
+&& patch -l -p1 <<EOF
+diff --git a/acorn-loose/rollup.config.js b/acorn-loose/rollup.config.js
+index d2389b2..c37882b 100644
+--- a/acorn-loose/rollup.config.js
++++ b/acorn-loose/rollup.config.js
+@@ -1,2 +0,0 @@
+-import buble from "rollup-plugin-buble"
+-
+@@ -23 +20,0 @@ export default {
+-    buble({transforms: {dangerousForOf: true}})
+diff --git a/acorn-walk/rollup.config.js b/acorn-walk/rollup.config.js
+index 67dd613..8c28807 100644
+--- a/acorn-walk/rollup.config.js
++++ b/acorn-walk/rollup.config.js
+@@ -1,2 +0,0 @@
+-import buble from "rollup-plugin-buble"
+-
+@@ -19 +16,0 @@ export default {
+-    buble({transforms: {dangerousForOf: true}})
+diff --git a/acorn/rollup.config.bin.js b/acorn/rollup.config.bin.js
+index 8a082b0..b3eda60 100644
+--- a/acorn/rollup.config.bin.js
++++ b/acorn/rollup.config.bin.js
+@@ -1,2 +0,0 @@
+-import buble from "rollup-plugin-buble"
+-
+@@ -11 +9 @@ export default {
+-  plugins: [buble()]
++  plugins: []
+diff --git a/acorn/rollup.config.js b/acorn/rollup.config.js
+index c775a0c..cfd4c68 100644
+--- a/acorn/rollup.config.js
++++ b/acorn/rollup.config.js
+@@ -1,2 +0,0 @@
+-import buble from "rollup-plugin-buble"
+-
+@@ -19 +16,0 @@ export default {
+-    buble({transforms: {dangerousForOf: true}})
+diff --git a/package.json b/package.json
+index 382f59e..4612a75 100644
+--- a/package.json
++++ b/package.json
+@@ -24,4 +24 @@
+-    "prepare": "npm run test",
+-    "test": "node test/run.js && node test/lint.js",
+-    "pretest": "npm run build:main && npm run build:loose",
+-    "test:test262": "node bin/run_test262.js",
++    "test": "node test/run.js",
+@@ -32,2 +29 @@
+-    "build:bin": "rollup -c acorn/rollup.config.bin.js",
+-    "lint": "eslint acorn/src/ acorn-walk/src/ acorn-loose/src/"
++    "build:bin": "rollup -c acorn/rollup.config.bin.js"
+@@ -36,6 +31,0 @@
+-    "eslint": "^4.10.0",
+-    "eslint-config-standard": "^10.2.1",
+-    "eslint-plugin-import": "^2.2.0",
+-    "eslint-plugin-node": "^5.2.1",
+-    "eslint-plugin-promise": "^3.5.0",
+-    "eslint-plugin-standard": "^3.0.1",
+@@ -43,4 +32,0 @@
+-    "rollup-plugin-buble": "^0.19.0",
+-    "test262": "git+https://github.com/tc39/test262.git#a6c819ad0f049f23f1a37af6b89dbb79fe3b9216",
+-    "test262-parser-runner": "^0.5.0",
+-    "test262-stream": "^1.2.1",
+EOF
+ERR=$?; if [ "$ERR" != "0" ]; then echo "Error: $ERR"; exit $ERR; fi
+minify_in_situ "acorn/src" \
+&& minify_in_situ "acorn-loose/src" \
+&& minify_in_situ "acorn-walk/src" \
+&& rm -rf node_modules \
+&& npm_install \
+&& rm -rf acorn/dist acorn-loose/dist acorn-walk/dist \
+&& npm run build \
+&& minify_in_situ "acorn/dist" \
+&& minify_in_situ "acorn-loose/dist" \
+&& minify_in_situ "acorn-walk/dist" \
+&& npm test

test/release/bootstrap.sh

@@ -0,0 +1,189 @@
+#!/bin/sh
+
+alias uglify-js=$PWD/bin/uglifyjs
+UGLIFY_OPTIONS=$@
+
+minify_in_situ() {
+    ARGS="$UGLIFY_OPTIONS --validate --in-situ"
+    DIRS="$1"
+    echo '> uglify-js' $DIRS $UGLIFY_OPTIONS
+    for i in `find $DIRS -type f -name '*.js'`
+    do
+        ARGS="$ARGS $i"
+    done
+    uglify-js $ARGS
+}
+
+npm_install() {
+    PKG="$1"
+    while !(npm install $PKG); do
+        while !(npm cache clean --force); do echo "'npm cache clean' failed - retrying..."; done
+    done
+}
+
+rm -rf tmp/bootstrap \
+&& git clone --depth 1 --branch v5.0.0-beta2 https://github.com/twbs/bootstrap.git tmp/bootstrap \
+&& cd tmp/bootstrap \
+&& rm -rf .git/hooks \
+&& patch -p1 <<EOF
+--- a/.babelrc.js
++++ /dev/null
+@@ -1,12 +0,0 @@
+-module.exports = {
+-  presets: [
+-    [
+-      '@babel/preset-env',
+-      {
+-        loose: true,
+-        bugfixes: true,
+-        modules: false
+-      }
+-    ]
+-  ]
+-};
+--- a/.gitattributes
++++ b/.gitattributes
+@@ -5,0 +6 @@
++*.png binary
+--- a/build/build-plugins.js
++++ b/build/build-plugins.js
+@@ -14 +13,0 @@ const rollup = require('rollup')
+-const { babel } = require('@rollup/plugin-babel')
+@@ -19,6 +17,0 @@ const plugins = [
+-  babel({
+-    // Only transpile our source code
+-    exclude: 'node_modules/**',
+-    // Include the helpers in each file, at most one copy of each
+-    babelHelpers: 'bundled'
+-  })
+--- a/build/rollup.config.js
++++ b/build/rollup.config.js
+@@ -4 +3,0 @@ const path = require('path')
+-const { babel } = require('@rollup/plugin-babel')
+@@ -15,6 +13,0 @@ const plugins = [
+-  babel({
+-    // Only transpile our source code
+-    exclude: 'node_modules/**',
+-    // Include the helpers in the bundle, at most one copy of each
+-    babelHelpers: 'bundled'
+-  })
+--- a/js/tests/integration/rollup.bundle.js
++++ b/js/tests/integration/rollup.bundle.js
+@@ -3 +2,0 @@
+-const { babel } = require('@rollup/plugin-babel')
+@@ -18,4 +16,0 @@ module.exports = {
+-    babel({
+-      exclude: 'node_modules/**',
+-      babelHelpers: 'bundled'
+-    })
+--- a/js/tests/karma.conf.js
++++ b/js/tests/karma.conf.js
+@@ -7,2 +6,0 @@ const ip = require('ip')
+-const { babel } = require('@rollup/plugin-babel')
+-const istanbul = require('rollup-plugin-istanbul')
+@@ -84,13 +81,0 @@ const conf = {
+-      istanbul({
+-        exclude: [
+-          'node_modules/**',
+-          'js/tests/unit/**/*.spec.js',
+-          'js/tests/helpers/**/*.js'
+-        ]
+-      }),
+-      babel({
+-        // Only transpile our source code
+-        exclude: 'node_modules/**',
+-        // Inline the required helpers in each file
+-        babelHelpers: 'inline'
+-      }),
+@@ -142 +126,0 @@ if (BROWSERSTACK) {
+-    'karma-coverage-istanbul-reporter'
+@@ -144 +127,0 @@ if (BROWSERSTACK) {
+-  reporters.push('coverage-istanbul')
+--- a/package.json
++++ b/package.json
+@@ -23 +23 @@
+-    "start": "npm-run-all --parallel watch docs-serve",
++    "start": "npm-run-all --parallel watch",
+@@ -28,3 +27,0 @@
+-    "css-lint": "npm-run-all --continue-on-error --parallel css-lint-*",
+-    "css-lint-stylelint": "stylelint \"**/*.{css,scss}\" --cache --cache-location .cache/.stylelintcache --rd",
+-    "css-lint-vars": "fusv scss/ site/assets/scss/",
+@@ -44 +40,0 @@
+-    "js-lint": "eslint --cache --cache-location .cache/.eslintcache --report-unused-disable-directives .",
+@@ -46,3 +42,3 @@
+-    "js-minify-standalone": "terser --compress passes=2 --mangle --comments \"/^!/\" --source-map \"content=dist/js/bootstrap.js.map,includeSources,url=bootstrap.min.js.map\" --output dist/js/bootstrap.min.js dist/js/bootstrap.js",
+-    "js-minify-standalone-esm": "terser --compress passes=2 --mangle --comments \"/^!/\" --source-map \"content=dist/js/bootstrap.esm.js.map,includeSources,url=bootstrap.esm.min.js.map\" --output dist/js/bootstrap.esm.min.js dist/js/bootstrap.esm.js",
+-    "js-minify-bundle": "terser --compress passes=2 --mangle --comments \"/^!/\" --source-map \"content=dist/js/bootstrap.bundle.js.map,includeSources,url=bootstrap.bundle.min.js.map\" --output dist/js/bootstrap.bundle.min.js dist/js/bootstrap.bundle.js",
++    "js-minify-standalone": "../../bin/uglifyjs --compress passes=2 --mangle --comments \"/^!/\" --source-map \"content=dist/js/bootstrap.js.map,includeSources,url=bootstrap.min.js.map\" --output dist/js/bootstrap.min.js dist/js/bootstrap.js",
++    "js-minify-standalone-esm": "../../bin/uglifyjs --compress passes=2 --mangle --comments \"/^!/\" --source-map \"content=dist/js/bootstrap.esm.js.map,includeSources,url=bootstrap.esm.min.js.map\" --output dist/js/bootstrap.esm.min.js dist/js/bootstrap.esm.js",
++    "js-minify-bundle": "../../bin/uglifyjs --compress passes=2 --mangle --comments \"/^!/\" --source-map \"content=dist/js/bootstrap.bundle.js.map,includeSources,url=bootstrap.bundle.min.js.map\" --output dist/js/bootstrap.bundle.min.js dist/js/bootstrap.bundle.js",
+@@ -56,25 +52 @@
+-    "lint": "npm-run-all --parallel js-lint css-lint lockfile-lint",
+-    "docs": "npm-run-all docs-build docs-lint",
+-    "docs-build": "hugo --cleanDestinationDir",
+-    "docs-compile": "npm run docs-build",
+-    "docs-linkinator": "linkinator _gh_pages --recurse --silent --skip \"^(?!http://localhost)\"",
+-    "docs-vnu": "node build/vnu-jar.js",
+-    "docs-lint": "npm-run-all --parallel docs-vnu docs-linkinator",
+-    "docs-serve": "hugo server --port 9001 --disableFastRender",
+-    "docs-serve-only": "npx sirv-cli _gh_pages --port 9001",
+-    "lockfile-lint": "lockfile-lint --allowed-hosts npm --allowed-schemes https: --empty-hostname false --type npm --path package-lock.json",
+-    "update-deps": "ncu -u -x karma-browserstack-launcher,terser && npm update && echo Manually update site/assets/js/vendor",
+-    "release": "npm-run-all dist release-sri docs-build release-zip*",
+-    "release-sri": "node build/generate-sri.js",
+-    "release-version": "node build/change-version.js",
+-    "release-zip": "cross-env-shell \"rm -rf bootstrap-\$npm_package_version-dist && cp -r dist/ bootstrap-\$npm_package_version-dist && zip -r9 bootstrap-\$npm_package_version-dist.zip bootstrap-\$npm_package_version-dist && rm -rf bootstrap-\$npm_package_version-dist\"",
+-    "release-zip-examples": "node build/zip-examples.js",
+-    "dist": "npm-run-all --parallel css js",
+-    "test": "npm-run-all lint dist js-test docs-build docs-lint",
+-    "netlify": "cross-env-shell HUGO_BASEURL=\$DEPLOY_PRIME_URL npm-run-all dist release-sri docs-build",
+-    "watch": "npm-run-all --parallel watch-*",
+-    "watch-css-main": "nodemon --watch scss/ --ext scss --exec \"npm-run-all css-lint css-compile css-prefix\"",
+-    "watch-css-dist": "nodemon --watch dist/css/ --ext css --ignore \"dist/css/*.rtl.*\" --exec \"npm run css-rtl\"",
+-    "watch-css-docs": "nodemon --watch site/assets/scss/ --ext scss --exec \"npm run css-lint\"",
+-    "watch-js-main": "nodemon --watch js/src/ --ext js --exec \"npm-run-all js-lint js-compile\"",
+-    "watch-js-docs": "nodemon --watch site/assets/js/ --ext js --exec \"npm run js-lint\""
++    "dist": "npm run css && npm run js"
+@@ -103,3 +74,0 @@
+-    "@babel/cli": "^7.12.13",
+-    "@babel/core": "^7.12.13",
+-    "@babel/preset-env": "^7.12.13",
+@@ -107 +75,0 @@
+-    "@rollup/plugin-babel": "^5.2.3",
+@@ -115,4 +82,0 @@
+-    "eslint": "^7.19.0",
+-    "eslint-config-xo": "^0.34.0",
+-    "eslint-plugin-import": "^2.22.1",
+-    "eslint-plugin-unicorn": "^27.0.0",
+@@ -122 +85,0 @@
+-    "hugo-bin": "^0.68.0",
+@@ -128 +90,0 @@
+-    "karma-coverage-istanbul-reporter": "^3.0.3",
+@@ -134,2 +95,0 @@
+-    "linkinator": "^2.13.4",
+-    "lockfile-lint": "^4.3.7",
+@@ -141 +100,0 @@
+-    "rollup-plugin-istanbul": "^3.0.0",
+@@ -144,5 +103 @@
+-    "shelljs": "^0.8.4",
+-    "stylelint": "^13.9.0",
+-    "stylelint-config-twbs-bootstrap": "^2.1.0",
+-    "terser": "5.1.0",
+-    "vnu-jar": "21.2.5"
++    "shelljs": "^0.8.4"
+@@ -155,3 +109,0 @@
+-  "hugo-bin": {
+-    "buildTags": "extended"
+-  },
+EOF
+ERR=$?; if [ "$ERR" != "0" ]; then echo "Error: $ERR"; exit $ERR; fi
+rm -rf node_modules \
+&& npm_install \
+&& minify_in_situ "node_modules/@popperjs/core" \
+&& rm -rf dist/js/* \
+&& minify_in_situ "build" \
+&& minify_in_situ "js" \
+&& minify_in_situ "site" \
+&& npm run dist \
+&& minify_in_situ "dist" \
+&& npm run js-test

test/release/buble.sh

@@ -0,0 +1,52 @@
+#!/bin/sh
+
+alias uglify-js=$PWD/bin/uglifyjs
+UGLIFY_OPTIONS=$@
+
+minify_in_situ() {
+    ARGS="$UGLIFY_OPTIONS --validate --in-situ"
+    DIRS="$1"
+    echo '> uglify-js' $DIRS $UGLIFY_OPTIONS
+    for i in `find $DIRS -type f -name '*.js'`
+    do
+        ARGS="$ARGS $i"
+    done
+    uglify-js $ARGS
+}
+
+npm_install() {
+    PKG="$1"
+    while !(npm install $PKG); do
+        while !(npm cache clean --force); do echo "'npm cache clean' failed - retrying..."; done
+    done
+}
+
+rm -rf tmp/buble \
+&& git clone https://github.com/bublejs/buble.git tmp/buble \
+&& cd tmp/buble \
+&& rm -rf .git/hooks \
+&& git checkout dcc5ab02c9af6ddaad94e587c4911677340ec100 \
+&& patch -l -p1 <<EOF
+--- a/package.json
++++ b/package.json
+@@ -29 +28,0 @@
+-    "prepublish": "npm test",
+@@ -67,3 +66 @@
+-    "source-map-support": "^0.5.16",
+-    "test262": "git+https://github.com/tc39/test262.git#4f1155c566a222238fd86f179c6635ecb4c289bb",
+-    "test262-stream": "^1.3.0"
++    "source-map-support": "^0.5.16"
+--- a/src/program/BlockStatement.js
++++ b/src/program/BlockStatement.js
+@@ -309 +309 @@ export default class BlockStatement extends Node {
+-                               let cont = false; // TODO implement proper continue...
++                               let cont = !declarations; // TODO implement proper continue...
+EOF
+ERR=$?; if [ "$ERR" != "0" ]; then echo "Error: $ERR"; exit $ERR; fi
+minify_in_situ "src" \
+&& rm -rf node_modules \
+&& npm_install \
+&& rm -rf dist \
+&& npm run build \
+&& minify_in_situ "dist" \
+&& node_modules/.bin/mocha

test/release/butternut.sh

@@ -0,0 +1,52 @@
+#!/bin/sh
+
+alias uglify-js=$PWD/bin/uglifyjs
+UGLIFY_OPTIONS=$@
+
+minify_in_situ() {
+    ARGS="$UGLIFY_OPTIONS --validate --in-situ"
+    DIRS="$1"
+    echo '> uglify-js' $DIRS $UGLIFY_OPTIONS
+    for i in `find $DIRS -type f -name '*.js'`
+    do
+        ARGS="$ARGS $i"
+    done
+    uglify-js $ARGS
+}
+
+npm_install() {
+    PKG="$1"
+    while !(npm install $PKG); do
+        while !(npm cache clean --force); do echo "'npm cache clean' failed - retrying..."; done
+    done
+}
+
+rm -rf tmp/butternut \
+&& git clone https://github.com/Rich-Harris/butternut.git tmp/butternut \
+&& cd tmp/butternut \
+&& rm -rf .git/hooks \
+&& patch -l -p1 <<EOF
+--- a/package.json
++++ b/package.json
+@@ -25 +24,0 @@
+-    "prepublish": "npm run test:min",
+--- a/rollup.config.js
++++ b/rollup.config.js
+@@ -1 +0,0 @@
+-import buble from 'rollup-plugin-buble';
+@@ -28,6 +26,0 @@ const config = {
+-               buble({
+-                       include: ['src/**', 'node_modules/acorn/**'],
+-                       transforms: {
+-                               dangerousForOf: true
+-                       }
+-               }),
+EOF
+ERR=$?; if [ "$ERR" != "0" ]; then echo "Error: $ERR"; exit $ERR; fi
+minify_in_situ "src" \
+&& rm -rf node_modules \
+&& npm_install \
+&& rm -rf dist \
+&& npm run build \
+&& minify_in_situ "dist" \
+&& node_modules/.bin/mocha test/test.js

test/release/install.sh

@@ -0,0 +1,58 @@
+echo "::group::GitHub Environment Variables"
+echo "CI: $CI"
+echo "GITHUB_WORKFLOW: $GITHUB_WORKFLOW"
+echo "GITHUB_RUN_ID: $GITHUB_RUN_ID"
+echo "GITHUB_RUN_NUMBER: $GITHUB_RUN_NUMBER"
+echo "GITHUB_ACTION: $GITHUB_ACTION"
+echo "GITHUB_ACTIONS: $GITHUB_ACTIONS"
+echo "GITHUB_ACTOR: $GITHUB_ACTOR"
+echo "GITHUB_REPOSITORY: $GITHUB_REPOSITORY"
+echo "GITHUB_EVENT_NAME: $GITHUB_EVENT_NAME"
+echo "GITHUB_EVENT_PATH: $GITHUB_EVENT_PATH"
+echo "GITHUB_WORKSPACE: $GITHUB_WORKSPACE"
+echo "GITHUB_SHA: $GITHUB_SHA"
+echo "GITHUB_REF: $GITHUB_REF"
+echo "GITHUB_HEAD_REF: $GITHUB_HEAD_REF"
+echo "GITHUB_BASE_REF: $GITHUB_BASE_REF"
+echo "GITHUB_SERVER_URL: $GITHUB_SERVER_URL"
+echo "GITHUB_API_URL: $GITHUB_API_URL"
+echo "GITHUB_GRAPHQL_URL: $GITHUB_GRAPHQL_URL"
+echo "::endgroup::"
+
+if command -v timeout &> /dev/null; then NATIVE=1; fi
+timeout() {
+    T=$1
+    shift
+    shift
+    shift
+    expect <<EOF
+set timeout $T
+spawn -noecho sh -c "$@"
+expect timeout { exit 124 } eof
+catch wait ret
+exit [lindex \$ret 3]
+EOF
+    return $?
+}
+if [ $NATIVE ]; then unset -f timeout; fi
+
+while !(git clone --branch v1.6.0 --depth 1 https://github.com/jasongin/nvs.git ~/.nvs); do
+    rm -rf ~/.nvs
+done
+while ! timeout 60 bash -c ". ~/.nvs/nvs.sh add $NODE && nvs use $NODE"; do
+    cd ~/.nvs
+    while !(git clean -xdf); do echo "'git clean' failed - retrying..."; done
+    cd -
+done
+. ~/.nvs/nvs.sh --version
+nvs use $NODE
+node --version
+npm config set audit false
+npm config set optional false
+npm config set save false
+npm config set strict-ssl false
+npm config set update-notifier false
+npm --version
+while !(npm install); do
+    while !(npm cache clean --force); do echo "'npm cache clean' failed - retrying..."; done
+done

test/release/mathjs.sh

@@ -0,0 +1,205 @@
+#!/bin/sh
+
+alias uglify-js=$PWD/bin/uglifyjs
+UGLIFY_OPTIONS="--annotations $@"
+
+minify_in_situ() {
+    ARGS="$UGLIFY_OPTIONS --validate --in-situ"
+    DIRS="$1"
+    echo '> uglify-js' $DIRS $UGLIFY_OPTIONS
+    for i in `find $DIRS -type f -name '*.js'`
+    do
+        ARGS="$ARGS $i"
+    done
+    for i in `find $DIRS -type f -name '*.mjs'`
+    do
+        ARGS="$ARGS $i"
+    done
+    uglify-js $ARGS
+}
+
+npm_install() {
+    PKG="$1"
+    while !(npm install $PKG); do
+        while !(npm cache clean --force); do echo "'npm cache clean' failed - retrying..."; done
+    done
+}
+
+rm -rf tmp/mathjs \
+&& git clone --depth 1 --branch v9.2.0 https://github.com/josdejong/mathjs.git tmp/mathjs \
+&& cd tmp/mathjs \
+&& rm -rf .git/hooks \
+&& patch -l -p1 <<EOF
+--- a/gulpfile.cjs
++++ b/gulpfile.cjs
+@@ -74 +74 @@ const webpackConfig = {
+-  mode: 'production',
++  mode: 'development',
+--- a/package.json
++++ b/package.json
+@@ -132,2 +131,0 @@
+-    "prepublishOnly": "npm run test:all && npm run lint",
+-    "prepare": "npm run build",
+--- a/src/utils/string.js
++++ b/src/utils/string.js
+@@ -15,0 +16,7 @@ export function endsWith (text, search) {
++export function HACK (value) {
++  if (typeof value == "object") {
++    (value = Object.create(value)).valueOf = function() { return this }
++  }
++  return value
++}
++
+@@ -68 +75 @@ export function format (value, options) {
+-      return value.toString()
++      return HACK(value).toString()
+--- a/test/node-tests/cli/cli.test.js
++++ b/test/node-tests/cli/cli.test.js
+@@ -36 +35,0 @@ describe('command line interface', function () {
+-    const path2 = path.join(__dirname, 'script2')
+@@ -38,2 +37,2 @@ describe('command line interface', function () {
+-    run('"' + path1 + '" "' + path2 + '"', function (e, result) {
+-      assert.strictEqual(result, '2\n8\n')
++    run('"' + path1 + '"', function (e, result) {
++      assert.strictEqual(result, '2\n')
+--- a/test/unit-tests/expression/node/Node.test.js
++++ b/test/unit-tests/expression/node/Node.test.js
+@@ -157 +157 @@ describe('Node', function () {
+-    assert.throws(function () {
++    if (0) assert.throws(function () {
+--- a/test/unit-tests/expression/parse.test.js
++++ b/test/unit-tests/expression/parse.test.js
+@@ -0,0 +1 @@
++import { HACK } from '../../../src/utils/string.js'
+@@ -333 +334 @@ describe('parse', function () {
+-      assert.strictEqual(fmath.parse('1/3').compile().evaluate().toString(), '0.(3)')
++      assert.strictEqual(HACK(fmath.parse('1/3').compile().evaluate()).toString(), '0.(3)')
+--- a/test/unit-tests/function/arithmetic/abs.test.js
++++ b/test/unit-tests/function/arithmetic/abs.test.js
+@@ -0,0 +1 @@
++import { HACK } from '../../../../src/utils/string.js'
+@@ -35,3 +36,3 @@ describe('abs', function () {
+-    assert.strictEqual(abs(a).toString(), '0.(3)')
+-    assert.strictEqual(a.toString(), '-0.(3)')
+-    assert.strictEqual(abs(fraction('1/3')).toString(), '0.(3)')
++    assert.strictEqual(HACK(abs(a)).toString(), '0.(3)')
++    assert.strictEqual(HACK(a).toString(), '-0.(3)')
++    assert.strictEqual(HACK(abs(fraction('1/3'))).toString(), '0.(3)')
+--- a/test/unit-tests/function/arithmetic/addScalar.test.js
++++ b/test/unit-tests/function/arithmetic/addScalar.test.js
+@@ -0,0 +1 @@
++import { HACK } from '../../../../src/utils/string.js'
+@@ -71 +72 @@ describe('addScalar', function () {
+-    assert.strictEqual(a.toString(), '0.(3)')
++    assert.strictEqual(HACK(a).toString(), '0.(3)')
+@@ -73 +74 @@ describe('addScalar', function () {
+-    assert.strictEqual(add(math.fraction(1), math.fraction(1, 3)).toString(), '1.(3)')
++    assert.strictEqual(HACK(add(math.fraction(1), math.fraction(1, 3))).toString(), '1.(3)')
+--- a/test/unit-tests/function/arithmetic/ceil.test.js
++++ b/test/unit-tests/function/arithmetic/ceil.test.js
+@@ -0,0 +1 @@
++import { HACK } from '../../../../src/utils/string.js'
+@@ -88 +89 @@ describe('ceil', function () {
+-    assert.strictEqual(a.toString(), '0.(6)')
++    assert.strictEqual(HACK(a).toString(), '0.(6)')
+@@ -105 +106 @@ describe('ceil', function () {
+-    assert.strictEqual(a.toString(), '0.(6)')
++    assert.strictEqual(HACK(a).toString(), '0.(6)')
+@@ -107 +108 @@ describe('ceil', function () {
+-    assert.strictEqual(a.toString(), '0.(6)')
++    assert.strictEqual(HACK(a).toString(), '0.(6)')
+--- a/test/unit-tests/function/arithmetic/fix.test.js
++++ b/test/unit-tests/function/arithmetic/fix.test.js
+@@ -0,0 +1 @@
++import { HACK } from '../../../../src/utils/string.js'
+@@ -107 +108 @@ describe('fix', function () {
+-    assert.strictEqual(a.toString(), '0.(6)')
++    assert.strictEqual(HACK(a).toString(), '0.(6)')
+@@ -124 +125 @@ describe('fix', function () {
+-    assert.strictEqual(a.toString(), '0.(6)')
++    assert.strictEqual(HACK(a).toString(), '0.(6)')
+@@ -127 +128 @@ describe('fix', function () {
+-    assert.strictEqual(b.toString(), '-0.(6)')
++    assert.strictEqual(HACK(b).toString(), '-0.(6)')
+--- a/test/unit-tests/function/arithmetic/floor.test.js
++++ b/test/unit-tests/function/arithmetic/floor.test.js
+@@ -0,0 +1 @@
++import { HACK } from '../../../../src/utils/string.js'
+@@ -96 +97 @@ describe('floor', function () {
+-    assert.strictEqual(a.toString(), '0.(6)')
++    assert.strictEqual(HACK(a).toString(), '0.(6)')
+--- a/test/unit-tests/function/arithmetic/gcd.test.js
++++ b/test/unit-tests/function/arithmetic/gcd.test.js
+@@ -0,0 +1 @@
++import { HACK } from '../../../../src/utils/string.js'
+@@ -62 +63 @@ describe('gcd', function () {
+-    assert.strictEqual(gcd(a, math.fraction(3, 7)).toString(), '0.017(857142)')
++    assert.strictEqual(HACK(gcd(a, math.fraction(3, 7))).toString(), '0.017(857142)')
+--- a/test/unit-tests/function/arithmetic/multiply.test.js
++++ b/test/unit-tests/function/arithmetic/multiply.test.js
+@@ -0,0 +1 @@
++import { HACK } from '../../../../src/utils/string.js'
+@@ -129 +130 @@ describe('multiply', function () {
+-      assert.strictEqual(multiply(math.fraction(2), math.fraction(1, 3)).toString(), '0.(6)')
++      assert.strictEqual(HACK(multiply(math.fraction(2), math.fraction(1, 3))).toString(), '0.(6)')
+--- a/test/unit-tests/function/arithmetic/round.test.js
++++ b/test/unit-tests/function/arithmetic/round.test.js
+@@ -0,0 +1 @@
++import { HACK } from '../../../../src/utils/string.js'
+@@ -82 +83 @@ describe('round', function () {
+-    assert.strictEqual(a.toString(), '0.(6)')
++    assert.strictEqual(HACK(a).toString(), '0.(6)')
+--- a/test/unit-tests/function/arithmetic/subtract.test.js
++++ b/test/unit-tests/function/arithmetic/subtract.test.js
+@@ -0,0 +1 @@
++import { HACK } from '../../../../src/utils/string.js'
+@@ -76,2 +77,2 @@ describe('subtract', function () {
+-    assert.strictEqual(subtract(a, math.fraction(1, 6)).toString(), '0.1(6)')
+-    assert.strictEqual(a.toString(), '0.(3)')
++    assert.strictEqual(HACK(subtract(a, math.fraction(1, 6))).toString(), '0.1(6)')
++    assert.strictEqual(HACK(a).toString(), '0.(3)')
+@@ -80 +81 @@ describe('subtract', function () {
+-    assert.strictEqual(subtract(math.fraction(1), math.fraction(1, 3)).toString(), '0.(6)')
++    assert.strictEqual(HACK(subtract(math.fraction(1), math.fraction(1, 3))).toString(), '0.(6)')
+--- a/test/unit-tests/function/arithmetic/unaryMinus.test.js
++++ b/test/unit-tests/function/arithmetic/unaryMinus.test.js
+@@ -0,0 +1 @@
++import { HACK } from '../../../../src/utils/string.js'
+@@ -31 +32 @@ describe('unaryMinus', function () {
+-    assert.deepStrictEqual(math.unaryMinus(bignumber(0)).toString(), '0')
++    assert.deepStrictEqual(HACK(math.unaryMinus(bignumber(0))).toString(), '0')
+--- a/test/unit-tests/function/relational/compare.test.js
++++ b/test/unit-tests/function/relational/compare.test.js
+@@ -0,0 +1 @@
++import { HACK } from '../../../../src/utils/string.js'
+@@ -76,2 +77,2 @@ describe('compare', function () {
+-    assert.strictEqual(a.toString(), '0.(3)')
+-    assert.strictEqual(b.toString(), '0.1(6)')
++    assert.strictEqual(HACK(a).toString(), '0.(3)')
++    assert.strictEqual(HACK(b).toString(), '0.1(6)')
+--- a/test/unit-tests/function/relational/compareNatural.test.js
++++ b/test/unit-tests/function/relational/compareNatural.test.js
+@@ -0,0 +1 @@
++import { HACK } from '../../../../src/utils/string.js'
+@@ -57,2 +58,2 @@ describe('compareNatural', function () {
+-    assert.strictEqual(a.toString(), '0.(3)')
+-    assert.strictEqual(b.toString(), '0.1(6)')
++    assert.strictEqual(HACK(a).toString(), '0.(3)')
++    assert.strictEqual(HACK(b).toString(), '0.1(6)')
+--- a/test/unit-tests/type/matrix/Matrix.test.js
++++ b/test/unit-tests/type/matrix/Matrix.test.js
+@@ -44 +44 @@ describe('matrix', function () {
+-      assert.throws(function () { m.toString() }, /Cannot invoke toString on a Matrix interface/)
++      if (0) assert.throws(function () { m.toString() }, /Cannot invoke toString on a Matrix interface/)
+EOF
+ERR=$?; if [ "$ERR" != "0" ]; then echo "Error: $ERR"; exit $ERR; fi
+minify_in_situ "bin" \
+&& minify_in_situ "src" \
+&& minify_in_situ "test" \
+&& minify_in_situ "tools" \
+&& rm -rf node_modules \
+&& npm_install \
+&& rm -rf lib \
+&& npm run build \
+&& minify_in_situ "lib" \
+&& npm run test:all

test/release/rollup-es.sh

@@ -0,0 +1,91 @@
+#!/bin/sh
+
+alias uglify-js=$PWD/bin/uglifyjs
+UGLIFY_OPTIONS=$@
+
+minify_in_situ() {
+    ARGS="$UGLIFY_OPTIONS --validate --in-situ"
+    DIRS="$1"
+    echo '> uglify-js' $DIRS $UGLIFY_OPTIONS
+    for i in `find $DIRS -type f -name '*.js'`
+    do
+        ARGS="$ARGS $i"
+    done
+    uglify-js $ARGS
+}
+
+npm_install() {
+    PKG="$1"
+    while !(npm install $PKG); do
+        while !(npm cache clean --force); do echo "'npm cache clean' failed - retrying..."; done
+    done
+}
+
+rm -rf tmp/rollup \
+&& git clone https://github.com/rollup/rollup.git tmp/rollup \
+&& cd tmp/rollup \
+&& rm -rf .git/hooks \
+&& git checkout 3d80c06f895eab41e648ee99786fa68c72458b80 \
+&& patch -l -p1 <<EOF
+--- a/package.json
++++ b/package.json
+@@ -23 +22,0 @@
+-    "prepublishOnly": "npm run lint && npm run test:only && npm run test:leak",
+--- a/rollup.config.js
++++ b/rollup.config.js
+@@ -1,5 +1,4 @@
+ import { readFileSync } from 'fs';
+-import buble from 'rollup-plugin-buble';
+ import resolve from 'rollup-plugin-node-resolve';
+ import commonjs from 'rollup-plugin-commonjs';
+ import json from 'rollup-plugin-json';
+@@ -25,12 +24,6 @@ export default [
+         input: 'src/node-entry.js',
+         plugins: [
+             json(),
+-            buble({
+-                include: ['src/**', 'node_modules/acorn/**'],
+-                target: {
+-                    node: '4'
+-                }
+-            }),
+             resolve(),
+             commonjs()
+         ],
+@@ -48,12 +41,6 @@ export default [
+         input: 'src/browser-entry.js',
+         plugins: [
+             json(),
+-            buble({
+-                include: ['src/**', 'node_modules/acorn/**'],
+-                target: {
+-                    node: '4'
+-                }
+-            }),
+             resolve(),
+             commonjs(),
+             {
+@@ -80,7 +67,6 @@ export default [
+         plugins: [
+             string({ include: '**/*.md' }),
+             json(),
+-            buble({ target: { node: 4 } }),
+             commonjs({
+                 include: 'node_modules/**'
+             }),
+--- a/test/mocha.opts
++++ b/test/mocha.opts
+@@ -1,2 +1 @@
+---require buble/register
+ test/test.js
+EOF
+ERR=$?; if [ "$ERR" != "0" ]; then echo "Error: $ERR"; exit $ERR; fi
+minify_in_situ "bin" \
+&& minify_in_situ "browser" \
+&& minify_in_situ "src" \
+&& rm -rf node_modules \
+&& npm_install \
+&& rm -rf dist \
+&& npm run build \
+&& minify_in_situ "dist" \
+&& node_modules/.bin/mocha

test/release/rollup-ts.sh

@@ -0,0 +1,63 @@
+#!/bin/sh
+
+alias uglify-js=$PWD/bin/uglifyjs
+UGLIFY_OPTIONS=$@
+
+minify_in_situ() {
+    ARGS="$UGLIFY_OPTIONS --validate --in-situ"
+    DIRS="$1"
+    echo '> esbuild' $DIRS
+    for i in `find $DIRS -type f -name '*.ts' | grep -v '\.d\.ts'`
+    do
+        echo "$i"
+        CODE=`cat "$i"`
+        node_modules/.bin/esbuild --loader=ts --target=esnext > "$i" <<EOF
+$CODE
+EOF
+        ARGS="$ARGS $i"
+    done
+    echo '> uglify-js' $DIRS $UGLIFY_OPTIONS
+    for i in `find $DIRS -type f -name '*.js'`
+    do
+        ARGS="$ARGS $i"
+    done
+    uglify-js $ARGS
+}
+
+npm_install() {
+    PKG="$1"
+    while !(npm install $PKG); do
+        while !(npm cache clean --force); do echo "'npm cache clean' failed - retrying..."; done
+    done
+}
+
+rm -rf tmp/rollup \
+&& git clone --depth 1 --branch v2.39.1 https://github.com/rollup/rollup.git tmp/rollup \
+&& cd tmp/rollup \
+&& rm -rf .git/hooks \
+&& patch -l -p1 <<EOF
+--- a/package.json
++++ b/package.json
+@@ -27,4 +26,0 @@
+-    "postinstall": "husky install",
+-    "postpublish": "pinst --enable",
+-    "prepare": "npm run build",
+-    "prepublishOnly": "pinst --disable && npm ci && npm run lint:nofix && npm run security && npm run build:bootstrap && npm run test:all",
+--- a/test/cli/index.js
++++ b/test/cli/index.js
+@@ -13,0 +14,3 @@ sander.rimrafSync(__dirname, 'node_modules');
++sander.rimrafSync(__dirname, 'samples', 'watch', 'bundle-error');
++sander.rimrafSync(__dirname, 'samples', 'watch', 'watch-config-error');
++sander.rimrafSync(__dirname, 'samples', 'watch', 'watch-config-initial-error');
+EOF
+ERR=$?; if [ "$ERR" != "0" ]; then echo "Error: $ERR"; exit $ERR; fi
+npm_install esbuild-wasm@0.8.56 \
+&& minify_in_situ "cli" \
+&& minify_in_situ "src" \
+&& rm -rf node_modules \
+&& npm_install \
+&& rm -rf dist \
+&& npm run build \
+&& minify_in_situ "dist" \
+&& node_modules/.bin/mocha test/test.js \
+&& node_modules/.bin/mocha test/browser/index.js

test/release/sucrase.sh

@@ -0,0 +1,101 @@
+#!/bin/sh
+
+alias uglify-js=$PWD/bin/uglifyjs
+UGLIFY_OPTIONS=$@
+
+minify_in_situ() {
+    ARGS="$UGLIFY_OPTIONS --validate --in-situ"
+    DIRS="$1"
+    echo '> esbuild' $DIRS
+    for i in `find $DIRS -type f -name '*.ts' | grep -v '\.d\.ts'`
+    do
+        echo "$i"
+        CODE=`cat "$i"`
+        node_modules/.bin/esbuild --loader=ts --target=esnext > "$i" <<EOF
+$CODE
+EOF
+        ARGS="$ARGS $i"
+    done
+    echo '> uglify-js' $DIRS $UGLIFY_OPTIONS
+    for i in `find $DIRS -type f -name '*.js'`
+    do
+        ARGS="$ARGS $i"
+    done
+    for i in `find $DIRS -type f -name '*.mjs'`
+    do
+        ARGS="$ARGS $i"
+    done
+    uglify-js $ARGS
+}
+
+npm_install() {
+    PKG="$1"
+    while !(npm install $PKG); do
+        while !(npm cache clean --force); do echo "'npm cache clean' failed - retrying..."; done
+    done
+}
+
+rm -rf tmp/sucrase \
+&& git clone https://github.com/alangpierce/sucrase.git tmp/sucrase \
+&& cd tmp/sucrase \
+&& rm -rf .git/hooks \
+&& git checkout 38b66f3009feb76750a799deea211adcc83574f1 \
+&& patch -l -p1 <<EOF
+--- a/package.json
++++ b/package.json
+@@ -25 +24,0 @@
+-    "prepublishOnly": "yarn clean && yarn build",
+@@ -65 +63,0 @@
+-    "test262-harness": "^6.5.0",
+--- a/script/build.ts
++++ b/script/build.ts
+@@ -16 +15,0 @@ async function main(): Promise<void> {
+-    () => buildBenchmark(),
+@@ -18,5 +16,0 @@ async function main(): Promise<void> {
+-    () => buildIntegration("./integrations/gulp-plugin"),
+-    () => buildIntegration("./integrations/jest-plugin"),
+-    () => buildIntegration("./integrations/webpack-loader"),
+-    () => buildIntegration("./integrations/webpack-object-rest-spread-plugin"),
+-    () => buildWebsite(),
+@@ -66,3 +59,0 @@ async function buildSucrase(): Promise<void> {
+-    // Also add in .d.ts files from tsc, which only need to be compiled once.
+-    await run(\`\${TSC} --project ./src --outDir ./dist-types\`);
+-    await mergeDirectoryContents("./dist-types/src", "./dist");
+@@ -70 +61 @@ async function buildSucrase(): Promise<void> {
+-    await run("yarn link");
++    await run("npm link");
+--- a/src/identifyShadowedGlobals.ts
++++ b/src/identifyShadowedGlobals.ts
+@@ -23,0 +24 @@ export default function identifyShadowedGlobals(
++export { identifyShadowedGlobals as HACK };
+--- a/src/parser/tokenizer/state.ts
++++ b/src/parser/tokenizer/state.ts
+@@ -100,0 +101 @@ export default class State {
++export { State as HACK };
+--- a/src/transformers/JSXTransformer.ts
++++ b/src/transformers/JSXTransformer.ts
+@@ -253,0 +254 @@ export default class JSXTransformer extends Transformer {
++export { JSXTransformer as HACK };
+--- a/src/util/getClassInfo.ts
++++ b/src/util/getClassInfo.ts
+@@ -164,0 +165 @@ export default function getClassInfo(
++export { getClassInfo as HACK };
+--- a/src/util/getDeclarationInfo.ts
++++ b/src/util/getDeclarationInfo.ts
+@@ -40,0 +41 @@ export default function getDeclarationInfo(tokens: TokenProcessor): DeclarationI
++export { getDeclarationInfo as HACK };
+--- a/src/util/getJSXPragmaInfo.ts
++++ b/src/util/getJSXPragmaInfo.ts
+@@ -14,0 +15 @@ export default function getJSXPragmaInfo(options: Options): JSXPragmaInfo {
++export { getJSXPragmaInfo as HACK };
+EOF
+ERR=$?; if [ "$ERR" != "0" ]; then echo "Error: $ERR"; exit $ERR; fi
+npm_install esbuild-wasm@0.8.56 \
+&& minify_in_situ "src" \
+&& rm -rf node_modules \
+&& npm_install \
+&& npm run clean \
+&& npm run build \
+&& minify_in_situ "dist" \
+&& minify_in_situ "dist-self-build" \
+&& npm run test-only

test/release/web-tooling-benchmark.sh

@@ -0,0 +1,65 @@
+#!/bin/sh
+
+alias uglify-js="node --max-old-space-size=8192 $PWD/bin/uglifyjs"
+UGLIFY_OPTIONS=$@
+
+minify_in_situ() {
+    ARGS="$UGLIFY_OPTIONS --validate --in-situ"
+    DIRS="$1"
+    echo '> uglify-js' $DIRS $UGLIFY_OPTIONS
+    for i in `find $DIRS -type f -name '*.js'`
+    do
+        ARGS="$ARGS $i"
+    done
+    uglify-js $ARGS
+}
+
+npm_install() {
+    PKG="$1"
+    while !(npm install $PKG); do
+        while !(npm cache clean --force); do echo "'npm cache clean' failed - retrying..."; done
+    done
+}
+
+rm -rf tmp/web-tooling-benchmark \
+&& git clone --depth 1 --branch v0.5.3 https://github.com/v8/web-tooling-benchmark.git tmp/web-tooling-benchmark \
+&& cd tmp/web-tooling-benchmark \
+&& rm -rf .git/hooks \
+&& patch -l -p1 <<EOF
+--- a/package.json
++++ b/package.json
+@@ -12 +11,0 @@
+-    "postinstall": "npm run build:terser-bundled && npm run build:uglify-js-bundled && npm run build",
+--- a/src/bootstrap.js
++++ b/src/bootstrap.js
+@@ -6 +6 @@ const gmean = require("compute-gmean");
+-const package = require("../package.json");
++const package_json = require("../package.json");
+@@ -65 +65 @@ function initialize() {
+-  document.title = \`Web Tooling Benchmark v\${package.version}\`;
++  document.title = \`Web Tooling Benchmark v\${package_json.version}\`;
+@@ -68 +68 @@ function initialize() {
+-  versionDiv.innerHTML = \`v\${package.version}\`;
++  versionDiv.innerHTML = \`v\${package_json.version}\`;
+--- a/src/cli-flags-helper.js
++++ b/src/cli-flags-helper.js
+@@ -7 +6,0 @@ const targetList = new Set([
+-  "chai",
+--- a/src/cli.js
++++ b/src/cli.js
+@@ -18,0 +19 @@ suite.on("error", event => {
++  global.process.exitCode = 42;
+EOF
+ERR=$?; if [ "$ERR" != "0" ]; then echo "Error: $ERR"; exit $ERR; fi
+minify_in_situ "src" \
+&& minify_in_situ "third_party" \
+&& rm -rf node_modules \
+&& npm_install \
+&& rm -rf build/* \
+&& npm run build:terser-bundled \
+&& npm run build:uglify-js-bundled \
+&& minify_in_situ "build" \
+&& rm -rf dist \
+&& npm run build \
+&& minify_in_situ "dist" \
+&& node dist/cli.js

test/sandbox.js

@@ -27,8 +27,8 @@ exports.run_code = semver.satisfies(process.version, "0.8") ? function(code, top
 } : semver.satisfies(process.version, "<0.12") ? run_code_vm : function(code, toplevel, timeout) {
     if ([
         /\basync[ \t]*\([\s\S]*?\)[ \t]*=>/,
-        /\b(async[ \t]+function|setInterval|setTimeout)\b/,
+        /\b(async[ \t]+function|Promise|setImmediate|setInterval|setTimeout)\b/,
-        /\basync([ \t]+|[ \t]*\*[ \t]*)[^\s()[\]{},.&|!~=*%/+-]+(\s*\(|[ \t]*=>)/,
+        /\basync([ \t]+|[ \t]*#|[ \t]*\*[ \t]*)[^\s()[\]{},.&|!~=*%/+-]+(\s*\(|[ \t]*=>)/,
     ].some(function(pattern) {
         return pattern.test(code);
     })) {
@@ -55,6 +55,8 @@ exports.patch_module_statements = function(code) {
         if (!header) return "";
         if (header.length == 1) return "0, " + header;
         return header.slice(0, -1) + " _" + ++count + header.slice(-1);
+    }).replace(/\bimport\.meta\b/g, function() {
+        return '({ url: "https://example.com/path/index.html" })';
     }).replace(/\bimport\b(?:\s*([^('"]+)\bfrom\b)?\s*(['"]).*?\2(?:$|\n|;)/g, function(match, symbols) {
         if (symbols) {
             if (!/^[{*]/.test(symbols)) symbols = "default:" + symbols;
@@ -175,12 +177,14 @@ function setup(global, builtins, setup_log, setup_tty) {
     [
         // for Node.js v0.12
         "Buffer",
+        "clearImmediate",
         "clearInterval",
         "clearTimeout",
         // for Node.js v0.12
         "DTRACE_NET_STREAM_END",
         // for Node.js v8
         "process",
+        "setImmediate",
         "setInterval",
         "setTimeout",
     ].forEach(function(name) {
@@ -198,9 +202,13 @@ function setup(global, builtins, setup_log, setup_tty) {
     });
     Object.defineProperties(global, props);
     // for Node.js v8+
-    global.toString = function() {
+    if (global.toString !== Object.prototype.toString) {
+        global.__proto__ = Object.defineProperty(Object.create(global.__proto__), "toString", {
+            value: function() {
                 return "[object global]";
-    };
+            },
+        });
+    }
 
     function self() {
         return this;
@@ -214,7 +222,7 @@ function setup(global, builtins, setup_log, setup_tty) {
             if (arg === global) return "[object global]";
             if (/Error$/.test(arg.name)) return arg.toString();
             if (typeof arg.then == "function") return "[object Promise]";
-            arg.constructor.toString();
+            if (arg.constructor) arg.constructor.toString();
             var index = cache.original.indexOf(arg);
             if (index >= 0) return cache.replaced[index];
             if (--cache.level < 0) return "[object Object]";

test/ufuzz/actions.js

@@ -1,7 +1,7 @@
 var get = require("https").get;
 var parse = require("url").parse;
 
-var base, token, run_number, eldest = true;
+var base, token, run_number;
 exports.init = function(url, auth, num) {
     base = url;
     token = auth;
@@ -19,14 +19,14 @@ exports.should_stop = function(callback) {
             do {
                 workflow = runs.pop();
                 if (!workflow) return;
-                if (workflow.event == "schedule" && workflow.run_number == run_number) found = true;
+                if (is_cron(workflow) && workflow.run_number == run_number) found = true;
             } while (!found && workflow.status == "completed");
             read(workflow.jobs_url, function(reply) {
                 if (!reply || !Array.isArray(reply.jobs)) return;
                 if (!reply.jobs.every(function(job) {
                     if (job.status == "completed") return true;
                     remaining--;
-                    return found || workflow.event != "schedule";
+                    return found || !is_cron(workflow);
                 })) return;
                 if (remaining >= 0) {
                     next();
@@ -38,6 +38,10 @@ exports.should_stop = function(callback) {
     });
 };
 
+function is_cron(workflow) {
+    return /^(schedule|workflow_dispatch|workflow_run)$/.test(workflow.event);
+}
+
 function read(url, callback) {
     var done = function(reply) {
         done = function() {};
@@ -56,7 +60,7 @@ function read(url, callback) {
         }).on("end", function() {
             var reply;
             try {
-                reply = JSON.parse(chunks.join(""))
+                reply = JSON.parse(chunks.join(""));
             } catch (e) {}
             done(reply);
         }).on("error", function() {

test/ufuzz/index.js

@@ -149,7 +149,10 @@ var SUPPORT = function(matrix) {
     for_of: "for (var a of []);",
     generator: "function* f(){}",
     let: "let a;",
+    logical_assignment: "[].p ??= 0;",
+    new_target: "function f() { new.target; }",
     nullish: "0 ?? 0",
+    optional_chaining: "0?.p",
     rest: "var [...a] = [];",
     rest_object: "var {...a} = {};",
     spread: "[...[]];",
@@ -157,6 +160,9 @@ var SUPPORT = function(matrix) {
     template: "``",
     trailing_comma: "function f(a,) {}",
 });
+if (SUPPORT.exponentiation && sandbox.run_code("console.log(10 ** 100 === Math.pow(10, 100));") !== "true\n") {
+    SUPPORT.exponentiation = false;
+}
 
 var VALUES = [
     '"a"',
@@ -184,9 +190,9 @@ var VALUES = [
     "25. ",
     "0x26.toString()",
     "NaN",
-    "undefined",
-    "Infinity",
     "null",
+    "Infinity",
+    "undefined",
     "[]",
     "[,0][1]", // an array with elisions... but this is always false
     "([,0].length === 2)", // an array with elisions... this is always true
@@ -199,12 +205,20 @@ var VALUES = [
     '"function"',
     "this",
 ];
+VALUES = VALUES.concat(VALUES);
+VALUES = VALUES.concat(VALUES);
+VALUES = VALUES.concat(VALUES);
 if (SUPPORT.bigint) VALUES = VALUES.concat([
     "(!0o644n)",
     "([3n][0] > 2)",
     "(-42n).toString()",
     "Number(0XDEADn << 16n | 0xbeefn)",
 ]);
+VALUES = VALUES.concat(VALUES);
+VALUES = VALUES.concat(VALUES);
+VALUES = VALUES.concat(VALUES);
+VALUES = VALUES.concat(VALUES);
+VALUES.push("import.meta");
 
 var BINARY_OPS = [
     " + ", // spaces needed to disambiguate with ++ cases (could otherwise cause syntax errors)
@@ -240,51 +254,31 @@ BINARY_OPS = BINARY_OPS.concat(BINARY_OPS);
 BINARY_OPS = BINARY_OPS.concat(BINARY_OPS);
 BINARY_OPS.push(" in ");
 
-var ASSIGNMENTS = [
+var ASSIGNMENTS = [ "=" ];
-    "=",
+ASSIGNMENTS = ASSIGNMENTS.concat(ASSIGNMENTS);
-    "=",
+ASSIGNMENTS.push("+=");
-    "=",
+ASSIGNMENTS = ASSIGNMENTS.concat(ASSIGNMENTS);
-    "=",
+ASSIGNMENTS = ASSIGNMENTS.concat(ASSIGNMENTS);
-    "=",
+ASSIGNMENTS = ASSIGNMENTS.concat(ASSIGNMENTS);
-    "=",
+ASSIGNMENTS = ASSIGNMENTS.concat([
-    "=",
-    "=",
-    "=",
-    "=",
-
-    "=",
-    "=",
-    "=",
-    "=",
-    "=",
-    "=",
-    "=",
-    "=",
-    "=",
-    "=",
-
-    "+=",
-    "+=",
-    "+=",
-    "+=",
-    "+=",
-    "+=",
-    "+=",
-    "+=",
-    "+=",
-    "+=",
-
     "-=",
     "*=",
     "/=",
+    "%=",
     "&=",
     "|=",
     "^=",
     "<<=",
     ">>=",
     ">>>=",
-    "%=",
+]);
-];
+ASSIGNMENTS = ASSIGNMENTS.concat(ASSIGNMENTS);
+if (SUPPORT.exponentiation) ASSIGNMENTS.push("**=");
+if (SUPPORT.logical_assignment) ASSIGNMENTS = ASSIGNMENTS.concat([
+    "&&=",
+    "||=",
+    "??=",
+]);
 
 var UNARY_SAFE = [
     "+",
@@ -362,12 +356,15 @@ var block_vars = [];
 var lambda_vars = [];
 var unique_vars = [];
 var classes = [];
+var allow_this = true;
 var async = false;
+var has_await = false;
 var export_default = false;
 var generator = false;
 var loops = 0;
 var funcs = 0;
 var clazz = 0;
+var imports = 0;
 var in_class = 0;
 var called = Object.create(null);
 var labels = 10000;
@@ -392,18 +389,29 @@ function appendExport(stmtDepth, allowDefault) {
     return "";
 }
 
+function mayDefer(code) {
+    if (SUPPORT.arrow && rng(200) == 0) {
+        has_await = true;
+        return "void setImmediate(() => (" + code + "))";
+    }
+    return code;
+}
+
 function createTopLevelCode() {
     VAR_NAMES.length = INITIAL_NAMES_LEN; // prune any previous names still in the list
     block_vars.length = 0;
     lambda_vars.length = 0;
     unique_vars.length = 0;
     classes.length = 0;
+    allow_this = true;
     async = false;
+    has_await = false;
     export_default = false;
     generator = false;
     loops = 0;
     funcs = 0;
     clazz = 0;
+    imports = 0;
     in_class = 0;
     called = Object.create(null);
     var s = [
@@ -419,7 +427,9 @@ function createTopLevelCode() {
         }
     });
     // preceding `null` makes for a cleaner output (empty string still shows up etc)
-    s.push("console.log(null, a, b, c, Infinity, NaN, undefined);");
+    var log = "console.log(null, a, b, c, Infinity, NaN, undefined)";
+    if (SUPPORT.arrow && has_await && rng(20) == 0) log = "setImmediate(() => " + log + ")";
+    s.push(log + ";");
     return s.join("\n");
 }
 
@@ -438,9 +448,9 @@ function addTrailingComma(list) {
 
 function createParams(was_async, was_generator, noDuplicate) {
     var save_async = async;
-    if (was_async) async = true;
+    if (!async) async = was_async;
     var save_generator = generator;
-    if (was_generator) generator = true;
+    if (!generator) generator = was_generator;
     var len = unique_vars.length;
     var params = [];
     for (var n = rng(4); --n >= 0;) {
@@ -562,9 +572,9 @@ function createAssignmentPairs(recurmax, stmtDepth, canThrow, nameLenBefore, was
     function createName() {
         unique_vars.push("a", "b", "c", "undefined", "NaN", "Infinity");
         var save_async = async;
-        if (was_async) async = true;
+        if (!async) async = was_async;
         var save_generator = generator;
-        if (was_generator) generator = true;
+        if (!generator) generator = was_generator;
         var name = createVarName(MANDATORY);
         generator = save_generator;
         async = save_async;
@@ -708,7 +718,7 @@ function createBlockVariables(recurmax, stmtDepth, canThrow, fn) {
         consts.forEach(addAvoidVar);
         lets.forEach(addAvoidVar);
         var s = [];
-        if (SUPPORT.class) while (rng(100) == 0) {
+        if (SUPPORT.class) while (rng(200) == 0) {
             var name = "C" + clazz++;
             classes.push(name);
             s.push(appendExport(stmtDepth, true) + createClassLiteral(recurmax, stmtDepth, canThrow, name));
@@ -806,8 +816,8 @@ function createFunction(recurmax, allowDefun, canThrow, stmtDepth) {
     var nameLenBefore = VAR_NAMES.length;
     var lambda_len = lambda_vars.length;
     var save_async = async;
-    async = SUPPORT.async && rng(50) == 0;
     var save_generator = generator;
+    async = SUPPORT.async && rng(200) == 0;
     generator = SUPPORT.generator && rng(50) == 0;
     if (async && generator && !SUPPORT.async_generator) {
         if (rng(2)) {
@@ -919,6 +929,21 @@ function getLabel(label) {
     return label && " L" + label;
 }
 
+function declareVarName(name, no_var) {
+    if (!SUPPORT.let || !no_var && rng(10)) return "var ";
+    block_vars.push(name);
+    return rng(2) ? "let " : "const ";
+}
+
+function createImportAlias() {
+    if (rng(10)) return "alias" + imports++;
+    unique_vars.push("a", "b", "c", "undefined", "NaN", "Infinity");
+    var name = createVarName(MANDATORY);
+    block_vars.push(name);
+    unique_vars.length -= 6;
+    return name;
+}
+
 function createStatement(recurmax, canThrow, canBreak, canContinue, cannotReturn, stmtDepth, target) {
     ++stmtDepth;
     var loop = ++loops;
@@ -955,20 +980,27 @@ function createStatement(recurmax, canThrow, canBreak, canContinue, cannotReturn
         canContinue = label.continue || enableLoopControl(canContinue, CAN_CONTINUE);
         return label.target + "for (var brake" + loop + " = 5; " + createExpression(recurmax, COMMA_OK, stmtDepth, canThrow) + " && brake" + loop + " > 0; --brake" + loop + ")" + createStatement(recurmax, canThrow, canBreak, canContinue, cannotReturn, stmtDepth);
       case STMT_FOR_ENUM:
+        var block_len = block_vars.length;
+        var nameLenBefore = VAR_NAMES.length;
         var label = createLabel(canBreak, canContinue);
         canBreak = label.break || enableLoopControl(canBreak, CAN_BREAK);
         canContinue = label.continue || enableLoopControl(canContinue, CAN_CONTINUE);
-        var key = rng(10) ? "key" + loop : getVarName(NO_CONST);
         var of = SUPPORT.for_of && rng(20) == 0;
+        var key;
+        if (rng(10)) {
+            key = "key" + loop;
+        } else if (bug_for_of_async && of) {
+            addAvoidVar("async");
+            key = getVarName(NO_CONST);
+            removeAvoidVar("async");
+        } else {
+            key = getVarName(NO_CONST);
+        }
         var init = "";
         if (!/^key/.test(key)) {
             if (!(of && bug_for_of_var) && rng(10) == 0) init = "var ";
-        } else if (!SUPPORT.let || !(of && bug_for_of_var) && rng(10)) {
-            init = "var ";
-        } else if (rng(2)) {
-            init = "let ";
         } else {
-            init = "const ";
+            init = declareVarName(key, of && bug_for_of_var);
         }
         if (!SUPPORT.destructuring || of && !(canThrow && rng(20) == 0) || rng(10)) {
             init += key;
@@ -997,14 +1029,29 @@ function createStatement(recurmax, canThrow, canBreak, canContinue, cannotReturn
                 s += '"" + (' + createExpression(recurmax, COMMA_OK, stmtDepth, canThrow) + "); ";
             }
             s += label.target + " for ";
-            if (await) s += "await ";
+            if (await) {
+                s += "await ";
+                has_await = true;
+            }
             s += "(" + init + " of expr" + loop + ") {";
         } else {
             s += createExpression(recurmax, COMMA_OK, stmtDepth, canThrow) + "; ";
             s += label.target + " for (" + init + " in expr" + loop + ") {";
         }
-        if (rng(3)) s += "c = 1 + c; var " + createVarName(MANDATORY) + " = expr" + loop + "[" + key + "]; ";
+        if (/^key/.test(key)) VAR_NAMES.push(key);
+        if (rng(3)) {
+            s += "c = 1 + c; ";
+            unique_vars.push("a", "b", "c", "undefined", "NaN", "Infinity");
+            var name;
+            do {
+                name = createVarName(MANDATORY);
+            } while (name == key);
+            unique_vars.length -= 6;
+            s += declareVarName(name) + name + " = expr" + loop + "[" + key + "]; ";
+        }
         s += createStatement(recurmax, canThrow, canBreak, canContinue, cannotReturn, stmtDepth) + "}";
+        VAR_NAMES.length = nameLenBefore;
+        block_vars.length = block_len;
         return "{" + s + "}";
       case STMT_SEMI:
         return use_strict && rng(20) === 0 ? '"use strict";' : ";";
@@ -1020,30 +1067,20 @@ function createStatement(recurmax, canThrow, canBreak, canContinue, cannotReturn
         return "switch (" + createExpression(recurmax, COMMA_OK, stmtDepth, canThrow) + ") { " + createSwitchParts(recurmax, 4, canThrow, canBreak, canContinue, cannotReturn, stmtDepth) + "}";
       case STMT_VAR:
         if (SUPPORT.destructuring && stmtDepth == 1 && rng(5) == 0) {
-            unique_vars.push("a", "b", "c", "undefined", "NaN", "Infinity");
+            var s = rng(2) ? " " + createImportAlias() : "";
-            var s = "";
-            if (rng(2)) {
-                var name = createVarName(MANDATORY);
-                block_vars.push(name);
-                s += " " + name;
-            }
             if (rng(10)) {
                 if (s) s += ",";
                 if (rng(2)) {
-                    var name = createVarName(MANDATORY);
+                    s += " * as " + createImportAlias();
-                    block_vars.push(name);
-                    s += " * as " + name;
                 } else {
                     var names = [];
                     for (var i = rng(4); --i >= 0;) {
-                        var name = createVarName(MANDATORY);
+                        var name = createImportAlias();
-                        block_vars.push(name);
                         names.push(rng(2) ? getDotKey() + " as " + name : name);
                     }
                     s += " { " + names.join(", ") + " }";
                 }
             }
-            unique_vars.length -= 6;
             if (s) s += " from";
             return "import" + s + ' "path/to/module.js";';
         } else if (SUPPORT.destructuring && rng(20) == 0) {
@@ -1154,7 +1191,7 @@ function createStatement(recurmax, canThrow, canBreak, canContinue, cannotReturn
 
 function createSwitchParts(recurmax, n, canThrow, canBreak, canContinue, cannotReturn, stmtDepth) {
     var hadDefault = false;
-    var s = [""];
+    var s = [ "" ];
     canBreak = enableLoopControl(canBreak, CAN_BREAK);
     while (n-- > 0) {
         //hadDefault = n > 0; // disables weird `default` clause positioning (use when handling destabilizes)
@@ -1191,7 +1228,10 @@ function createExpression(recurmax, noComma, stmtDepth, canThrow) {
         return "((c = c + 1) + (" + _createExpression(recurmax, noComma, stmtDepth, canThrow) + "))"; // c only gets incremented
       default:
         var expr = "(" + _createExpression(recurmax, noComma, stmtDepth, canThrow) + ")";
-        if (async && rng(50) == 0) return "(await" + expr + ")";
+        if (async && rng(50) == 0) {
+            has_await = true;
+            return "(await" + expr + ")";
+        }
         if (generator && rng(50) == 0) return "(yield" + (canThrow && rng(20) == 0 ? "*" : "") + expr + ")";
         return expr;
     }
@@ -1223,6 +1263,10 @@ function _createExpression(recurmax, noComma, stmtDepth, canThrow) {
       case p++:
         return createValue();
       case p++:
+        if (SUPPORT.destructuring && rng(20) == 0) {
+            var name = "alias" + rng(imports + 2);
+            return canThrow && rng(20) == 0 ? name : "typeof " + name + ' != "undefined" && ' + name;
+        }
       case p++:
         return getVarName();
       case p++:
@@ -1257,8 +1301,8 @@ function _createExpression(recurmax, noComma, stmtDepth, canThrow) {
         var nameLenBefore = VAR_NAMES.length;
         var lambda_len = lambda_vars.length;
         var save_async = async;
-        async = SUPPORT.async && rng(50) == 0;
         var save_generator = generator;
+        async = SUPPORT.async && rng(200) == 0;
         generator = SUPPORT.generator && rng(50) == 0;
         if (async && generator && !SUPPORT.async_generator) {
             if (rng(2)) {
@@ -1361,13 +1405,16 @@ function _createExpression(recurmax, noComma, stmtDepth, canThrow) {
             createBlockVariables(recurmax, stmtDepth, canThrow, function(defns) {
                 s.push(
                     instantiate + makeFunction(name) + "(" + createParams(save_async, save_generator) + "){",
-                    strictMode(),
+                    strictMode()
-                    defns()
                 );
+                var add_new_target = SUPPORT.new_target && VALUES.indexOf("new.target") < 0;
+                if (add_new_target) VALUES.push("new.target");
+                s.push(defns());
                 if (instantiate) for (var i = rng(4); --i >= 0;) {
                     s.push((in_class ? "if (this) " : "") + createThisAssignment(recurmax, stmtDepth, canThrow));
                 }
                 s.push(_createStatements(rng(5) + 1, recurmax, canThrow, CANNOT_BREAK, CANNOT_CONTINUE, CAN_RETURN, stmtDepth));
+                if (add_new_target) VALUES.splice(VALUES.indexOf("new.target"), 1);
             });
             generator = save_generator;
             async = save_async;
@@ -1443,23 +1490,30 @@ function _createExpression(recurmax, noComma, stmtDepth, canThrow) {
         return createValue() + " in " + createObjectLiteral(recurmax, stmtDepth, canThrow);
       case p++:
         var name = getVarName();
-        var s = name + "[" + createExpression(recurmax, COMMA_OK, stmtDepth, canThrow) + "]";
+        var prop = "[" + createExpression(recurmax, COMMA_OK, stmtDepth, canThrow) + "]";
-        return canThrow && rng(20) == 0 ? s : name + " && " + s;
+        if (SUPPORT.optional_chaining && rng(50) == 0) return name + "?." + prop;
+        if (canThrow && rng(20) == 0) return name + prop;
+        return name + " && " + name + prop;
       case p++:
         var name = getVarName();
-        var s = name + "." + getDotKey();
+        var prop = getDotKey();
-        return canThrow && rng(20) == 0 ? s : name + " && " + s;
+        if (SUPPORT.optional_chaining && rng(50) == 0) return name + "?." + prop;
+        if (canThrow && rng(20) == 0) return name + "." + prop;
+        return name + " && " + name + "." + prop;
       case p++:
       case p++:
         var name = getVarName();
-        var s = name + "." + getDotKey();
+        var fn = name + "." + getDotKey();
-        s = "typeof " + s + ' == "function" && --_calls_ >= 0 && ' + s + createArgs(recurmax, stmtDepth, canThrow);
+        var s = "typeof " + fn + ' == "function" && --_calls_ >= 0 && ';
-        return canThrow && rng(20) == 0 ? s : name + " && " + s;
+        s += rng(5) ? fn : "(" + createExpression(recurmax, NO_COMMA, stmtDepth, canThrow) + ", " + fn + ")";
+        s += createArgs(recurmax, stmtDepth, canThrow);
+        return mayDefer(canThrow && rng(20) == 0 ? s : name + " && " + s);
       case p++:
-        if (SUPPORT.class && classes.length) switch (rng(20)) {
+        if (SUPPORT.class) {
-          case 0:
+            if (classes.length && rng(20) == 0) {
                 return "--_calls_ >= 0 && new " + classes[rng(classes.length)] + createArgs(recurmax, stmtDepth, canThrow, NO_TEMPLATE);
-          case 1:
+            }
+            if (rng(200) == 0) {
                 var s = "--_calls_ >= 0 && new ";
                 var nameLenBefore = VAR_NAMES.length;
                 var class_len = classes.length;
@@ -1478,6 +1532,7 @@ function _createExpression(recurmax, noComma, stmtDepth, canThrow) {
                 s += createArgs(recurmax, stmtDepth, canThrow, NO_TEMPLATE);
                 return s;
             }
+        }
       case p++:
       case p++:
       case p++:
@@ -1486,7 +1541,16 @@ function _createExpression(recurmax, noComma, stmtDepth, canThrow) {
             name = rng(3) == 0 ? getVarName() : "f" + rng(funcs + 2);
         } while (name in called && !called[name]);
         called[name] = true;
-        return "typeof " + name + ' == "function" && --_calls_ >= 0 && ' + name + createArgs(recurmax, stmtDepth, canThrow);
+        var args = createArgs(recurmax, stmtDepth, canThrow);
+        var call = "typeof " + name + ' == "function" && --_calls_ >= 0 && ' + name + args;
+        if (canThrow) {
+            if (SUPPORT.optional_chaining && args[0] != "`" && rng(50) == 0) {
+                call = "--_calls_ >= 0 && " + name + "?." + args;
+            } else if (rng(20) == 0) {
+                call = "--_calls_ >= 0 && " + name + args;
+            }
+        }
+        return mayDefer(call);
     }
     _createExpression.N = p;
     return _createExpression(recurmax, noComma, stmtDepth, canThrow);
@@ -1546,15 +1610,19 @@ var SAFE_KEYS = [
     "a",
     "b",
     "c",
-    "undefined",
-    "null",
-    "NaN",
-    "Infinity",
-    "done",
     "foo",
+    "NaN",
+    "null",
+    "Infinity",
+    "undefined",
+    "async",
+    "done",
+    "get",
     "in",
     "length",
     "next",
+    "set",
+    "static",
     "then",
     "value",
     "var",
@@ -1567,6 +1635,10 @@ var KEYS = [
     "1.5",
     "3",
 ].concat(SAFE_KEYS);
+SAFE_KEYS = SAFE_KEYS.concat(SAFE_KEYS);
+SAFE_KEYS = SAFE_KEYS.concat(SAFE_KEYS);
+SAFE_KEYS = SAFE_KEYS.concat(SAFE_KEYS);
+SAFE_KEYS.push("__proto__");
 
 function getDotKey(assign) {
     var key;
@@ -1648,7 +1720,7 @@ function createObjectFunction(recurmax, stmtDepth, canThrow, internal, isClazz)
             generator = false;
             name = "constructor";
         } else {
-            async = SUPPORT.async && rng(50) == 0;
+            async = SUPPORT.async && rng(200) == 0;
             generator = SUPPORT.generator && rng(50) == 0;
             if (async && generator && !SUPPORT.async_generator) {
                 if (rng(2)) {
@@ -1661,6 +1733,8 @@ function createObjectFunction(recurmax, stmtDepth, canThrow, internal, isClazz)
         fn = function(defns) {
             if (generator) name = "*" + name;
             if (async) name = "async "+ name;
+            var save_allow = allow_this;
+            if (internal == "super") allow_this = false;
             s = [
                 name + "(" + createParams(save_async, save_generator, NO_DUPLICATE) + "){",
                 strictMode(),
@@ -1668,6 +1742,7 @@ function createObjectFunction(recurmax, stmtDepth, canThrow, internal, isClazz)
             ];
             s.push(_createStatements(2, recurmax, canThrow, CANNOT_BREAK, CANNOT_CONTINUE, CANNOT_RETURN, stmtDepth));
             if (internal == "super") s.push("super" + createArgs(recurmax, stmtDepth, canThrow, NO_TEMPLATE) + ";");
+            allow_this = save_allow;
             if (/^(constructor|super)$/.test(internal) || rng(10) == 0) for (var i = rng(4); --i >= 0;) {
                 s.push(rng(2) ? createSuperAssignment(recurmax, stmtDepth, canThrow) : createThisAssignment(recurmax, stmtDepth, canThrow));
             }
@@ -1684,8 +1759,9 @@ function createObjectFunction(recurmax, stmtDepth, canThrow, internal, isClazz)
 
 function createObjectLiteral(recurmax, stmtDepth, canThrow) {
     recurmax--;
-    var obj = ["({"];
+    var obj = [ "({" ];
     var offset = SUPPORT.spread_object ? 0 : SUPPORT.computed_key ? 2 : 4;
+    var has_proto = false;
     for (var i = rng(6); --i >= 0;) switch (offset + rng(50 - offset)) {
       case 0:
         obj.push("..." + getVarName() + ",");
@@ -1701,7 +1777,12 @@ function createObjectLiteral(recurmax, stmtDepth, canThrow) {
         obj.push(createObjectFunction(recurmax, stmtDepth, canThrow) + ",");
         break;
       default:
+        if (has_proto || rng(200)) {
             obj.push(createObjectKey(recurmax, stmtDepth, canThrow) + ": " + createExpression(recurmax, COMMA_OK, stmtDepth, canThrow) + ",");
+        } else {
+            obj.push("__proto__: " + createExpression(recurmax, COMMA_OK, stmtDepth, canThrow) + " || {},");
+            has_proto = true;
+        }
         break;
     }
     obj.push("})");
@@ -1744,7 +1825,7 @@ function createClassLiteral(recurmax, stmtDepth, canThrow, name) {
         if (SUPPORT.class_field && rng(2)) {
             s += internal || createObjectKey(recurmax, stmtDepth, canThrow);
             if (rng(5)) {
-                async = false;
+                async = bug_async_class_await && fixed && 0;
                 generator = false;
                 s += " = " + createExpression(recurmax, NO_COMMA, stmtDepth, fixed ? canThrow : CANNOT_THROW);
                 generator = save_generator;
@@ -1895,7 +1976,11 @@ function createTypeofExpr(recurmax, stmtDepth, canThrow) {
 }
 
 function createValue() {
-    return VALUES[rng(VALUES.length)];
+    var v;
+    do {
+        v = VALUES[rng(VALUES.length)];
+    } while (v == "new.target" && rng(200) || !allow_this && v == "this");
+    return v;
 }
 
 function createBinaryOp(noComma, canThrow) {
@@ -1944,7 +2029,7 @@ function isBannedKeyword(name) {
       case "arguments":
         return in_class;
       case "await":
-        return async;
+        return async !== false;
       case "yield":
         return generator || in_class;
     }
@@ -1989,6 +2074,7 @@ function createVarName(maybe, dontStore) {
 if (require.main !== module) {
     exports.createTopLevelCode = createTopLevelCode;
     exports.num_iterations = num_iterations;
+    exports.verbose = verbose;
     return;
 }
 
@@ -2167,8 +2253,7 @@ function log(options) {
 function sort_globals(code) {
     var globals = run_code("throw Object.keys(this).sort(" + function(global) {
         return function(m, n) {
-            return (n == "toString") - (m == "toString")
+            return (typeof global[n] == "function") - (typeof global[m] == "function")
-                || (typeof global[n] == "function") - (typeof global[m] == "function")
                 || (m < n ? -1 : m > n ? 1 : 0);
         };
     } + "(this));" + code);
@@ -2218,7 +2303,7 @@ function is_error_in(ex) {
 }
 
 function is_error_spread(ex) {
-    return ex.name == "TypeError" && /Found non-callable @@iterator| is not iterable| is not a function/.test(ex.message);
+    return ex.name == "TypeError" && /Found non-callable @@iterator| is not iterable| not a function/.test(ex.message);
 }
 
 function is_error_recursion(ex) {
@@ -2337,6 +2422,8 @@ if (SUPPORT.arrow && SUPPORT.async && SUPPORT.rest && typeof sandbox.run_code("a
         return ex.name == "SyntaxError" && ex.message == "Rest parameter must be last formal parameter";
     };
 }
+var bug_async_class_await = SUPPORT.async && SUPPORT.class_field && typeof sandbox.run_code("var await; async function f() { class A { static p = await; } }") != "string";
+var bug_for_of_async = SUPPORT.for_await_of && typeof sandbox.run_code("var async; for (async of []);") != "string";
 var bug_for_of_var = SUPPORT.for_of && SUPPORT.let && typeof sandbox.run_code("try {} catch (e) { for (var e of []); }") != "string";
 if (SUPPORT.destructuring && typeof sandbox.run_code("console.log([ 1 ], {} = 2);") != "string") {
     beautify_options.output.v8 = true;

tools/node.js

@@ -56,6 +56,9 @@ if (+process.env["UGLIFY_BUG_REPORT"]) exports.minify = function(files, options)
 
 function describe_ast() {
     var out = OutputStream({ beautify: true });
+    doitem(AST_Node);
+    return out.get() + "\n";
+
     function doitem(ctor) {
         out.print("AST_" + ctor.TYPE);
         var props = ctor.SELF_PROPS.filter(function(prop) {
@@ -86,9 +89,7 @@ function describe_ast() {
                 });
             });
         }
-    };
+    }
-    doitem(AST_Node);
-    return out + "\n";
 }
 
 function infer_options(options) {