harmony-v3.1.0

Avoid collision with local variable `undefined` under certain corner cases.

fixes #2298

.github/ISSUE_TEMPLATE.md

@@ -8,7 +8,14 @@
 
 **Uglify version (`uglifyjs -V`)**
 
-**JavaScript input**  <!-- ideally as small as possible -->
+**JavaScript input**
+
+<!--
+    A complete parsable JS program exhibiting the issue with
+    UglifyJS alone - without third party tools or libraries.
+    Ideally the input should be as small as possible.
+    Post a link to a gist if necessary.
+-->
 
 **The `uglifyjs` CLI command executed or `minify()` options used.**
 

README.md

@@ -1,7 +1,7 @@
 uglify-es
 =========
 
-**uglify-es** is an ECMAScript parser, minifier, compressor and beautifier toolkit for ES6+.
+A JavaScript parser, mangler/compressor and beautifier toolkit for ES6+.
 
 #### Note:
 - **`uglify-es` is API/CLI compatible with `uglify-js@3`.**
@@ -148,19 +148,19 @@ debugging your compressed JavaScript.  To get a source map, pass
 
 Additional options:
 
-- `--source-map filename=<NAME>` to specify the name of the source map.
+- `--source-map "filename='<NAME>'"` to specify the name of the source map.
 
-- `--source-map root=<URL>` to pass the URL where the original files can be found.
+- `--source-map "root='<URL>'"` to pass the URL where the original files can be found.
   Otherwise UglifyJS assumes HTTP `X-SourceMap` is being used and will omit the
   `//# sourceMappingURL=` directive.
 
-- `--source-map url=<URL>` to specify the URL where the source map can be found.
+- `--source-map "url='<URL>'"` to specify the URL where the source map can be found.
 
 For example:
 
     uglifyjs js/file1.js js/file2.js \
              -o foo.min.js -c -m \
-             --source-map root="http://foo.com/src",url=foo.min.js.map
+             --source-map "root='http://foo.com/src',url='foo.min.js.map'"
 
 The above will compress and mangle `file1.js` and `file2.js`, will drop the
 output in `foo.min.js` and the source map in `foo.min.js.map`.  The source
@@ -179,8 +179,8 @@ CoffeeScript → compiled JS, UglifyJS can generate a map from CoffeeScript →
 compressed JS by mapping every token in the compiled JS to its original
 location.
 
-To use this feature pass `--source-map content="/path/to/input/source.map"`
-or `--source-map content=inline` if the source map is included inline with
+To use this feature pass `--source-map "content='/path/to/input/source.map'"`
+or `--source-map "content=inline"` if the source map is included inline with
 the sources.
 
 ## CLI compress options
@@ -211,7 +211,7 @@ 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:
 
-    uglifyjs ... -m reserved=[$,require,exports]
+    uglifyjs ... -m reserved=['$','require','exports']
 
 to prevent the `require`, `exports` and `$` names from being changed.
 
@@ -646,9 +646,16 @@ If you're using the `X-SourceMap` header instead, you can just omit `sourceMap.u
 
 - `evaluate` -- attempt to evaluate constant expressions
 
-- `arrows` (default `true`) -- convert ES5 style anonymous function expressions
-  to arrow functions if permissible by language semantics.
-  Note: `arrows` requires that the `ecma` compress option is set to `6` or greater.
+- `arrows` (default `true`) -- Converts `()=>{return x}` to `()=>x`. Class
+  and object literal methods will also be converted to arrow expressions if
+  the resultant code is shorter: `m(){return x}` becomes `m:()=>x`.
+  This transform requires that the `ecma` compress option is set to `6` or greater.
+
+- `unsafe_arrows` (default `false`) -- Convert ES5 style anonymous function
+  expressions to arrow functions if the function body does not reference `this`.
+  Note: it is not always safe to perform this conversion if code relies on the
+  the function having a `prototype`, which arrow functions lack.
+  This transform requires that the `ecma` compress option is set to `6` or greater.
 
 - `booleans` -- various optimizations for boolean context, for example `!!a
   ? b : c → a ? b : c`
@@ -730,7 +737,7 @@ If you're using the `X-SourceMap` header instead, you can just omit `sourceMap.u
   compressor from discarding function names.  Useful for code relying on
   `Function.prototype.name`. See also: the `keep_fnames` [mangle option](#mangle).
 
-- `passes` -- default `1`. Number of times to run compress with a maximum of 3.
+- `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.
 
@@ -1056,8 +1063,8 @@ in total it's a bit more than just using UglifyJS's own parser.
 
 ### Uglify Fast Minify Mode
 
-It's not well known, but variable and function name mangling accounts for
-95% of the size reduction in minified code for most javascript - not
+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
 comparable minify speeds and gzip sizes to
@@ -1066,10 +1073,11 @@ comparable minify speeds and gzip sizes to
 | d3.js | minify size | gzip size | minify time (seconds) |
 | --- | ---: | ---: | ---: |
 | original | 451,131 | 108,733 | - |
-| uglify-js@3.0.23 mangle=false, compress=false | 316,600 | 85,245 | 0.73 |
-| uglify-js@3.0.23 mangle=true, compress=false | 220,216 | 72,730 | 1.21 |
-| Butternut 0.4.6 | 217,568 | 72,738 | 1.81 |
-| uglify-js@3.0.23 mangle=true, compress=true | 212,511 | 71,560 | 4.64 |
+| uglify-js@3.0.24 mangle=false, compress=false | 316,600 | 85,245 | 0.70 |
+| uglify-js@3.0.24 mangle=true, compress=false | 220,216 | 72,730 | 1.13 |
+| butternut@0.4.6 | 217,568 | 72,738 | 1.41 |
+| 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:
 ```

bin/uglifyjs

@@ -35,11 +35,11 @@ else if (process.argv.indexOf("options") >= 0) program.helpInformation = functio
     }
     return text.join("\n");
 };
-program.option("-p, --parse <options>", "Specify parser options.", parse_js("parse", true));
-program.option("-c, --compress [options]", "Enable compressor/specify compressor options.", parse_js("compress", true));
-program.option("-m, --mangle [options]", "Mangle names/specify mangler options.", parse_js("mangle", true));
-program.option("--mangle-props [options]", "Mangle properties/specify mangler options.", parse_js("mangle-props", true));
-program.option("-b, --beautify [options]", "Beautify output/specify output options.", parse_js("beautify", true));
+program.option("-p, --parse <options>", "Specify parser options.", parse_js());
+program.option("-c, --compress [options]", "Enable compressor/specify compressor options.", parse_js());
+program.option("-m, --mangle [options]", "Mangle names/specify mangler options.", parse_js());
+program.option("--mangle-props [options]", "Mangle properties/specify mangler options.", parse_js());
+program.option("-b, --beautify [options]", "Beautify output/specify output options.", parse_js());
 program.option("-o, --output <file>", "Output file (default STDOUT).");
 program.option("--comments [filter]", "Preserve copyright comments in the output.");
 program.option("--config-file <file>", "Read minify() options from JSON file.");
@@ -315,7 +315,7 @@ function read_file(path, default_value) {
     }
 }
 
-function parse_js(flag, constants) {
+function parse_js(flag) {
     return function(value, options) {
         options = options || {};
         try {
@@ -333,7 +333,7 @@ function parse_js(flag, constants) {
                 if (node instanceof UglifyJS.AST_Assign) {
                     var name = node.left.print_to_string();
                     var value = node.right;
-                    if (!constants) {
+                    if (flag) {
                         options[name] = value;
                     } else if (value instanceof UglifyJS.AST_Array) {
                         options[name] = value.elements.map(to_string);
@@ -356,14 +356,18 @@ function parse_js(flag, constants) {
                 }
             }));
         } catch(ex) {
-            options[value] = null;
+            if (flag) {
+                fatal("Error parsing arguments for '" + flag + "': " + value);
+            } else {
+                options[value] = null;
+            }
         }
         return options;
     }
 }
 
 function parse_source_map() {
-    var parse = parse_js("sourceMap", true);
+    var parse = parse_js();
     return function(value, options) {
         var hasContent = options && "content" in options;
         var settings = parse(value, options);

lib/ast.js

@@ -697,7 +697,7 @@ var AST_Export = DEFNODE("Export", "exported_definition exported_value is_defaul
 var AST_VarDef = DEFNODE("VarDef", "name value", {
     $documentation: "A variable declaration; only appears in a AST_Definitions node",
     $propdoc: {
-        name: "[AST_SymbolVar|AST_SymbolConst|AST_Destructuring] name of the variable",
+        name: "[AST_Destructuring|AST_SymbolConst|AST_SymbolLet|AST_SymbolVar] name of the variable",
         value: "[AST_Node?] initializer, or null of there's no initializer"
     },
     _walk: function(visitor) {

lib/compress.js

@@ -84,6 +84,7 @@ function Compressor(options, false_by_default) {
         toplevel      : !!(options && options["top_retain"]),
         typeofs       : !false_by_default,
         unsafe        : false,
+        unsafe_arrows : false,
         unsafe_comps  : false,
         unsafe_Func   : false,
         unsafe_math   : false,
@@ -151,10 +152,20 @@ merge(Compressor.prototype, {
             node.process_expression(true);
         }
         var passes = +this.options.passes || 1;
-        for (var pass = 0; pass < passes && pass < 3; ++pass) {
+        var last_count = 1 / 0;
+        for (var pass = 0; pass < passes; pass++) {
             if (pass > 0 || this.option("reduce_vars"))
                 node.reset_opt_flags(this, true);
             node = node.transform(this);
+            if (passes > 1) {
+                var count = 0;
+                node.walk(new TreeWalker(function() {
+                    count++;
+                }));
+                this.info("pass " + pass + ": last_count: " + last_count + ", count: " + count);
+                if (count >= last_count) break;
+                last_count = count;
+            }
         }
         if (this.option("expression")) {
             node.process_expression(false);
@@ -292,6 +303,7 @@ merge(Compressor.prototype, {
             if (reduce_vars) {
                 if (node instanceof AST_Toplevel) node.globals.each(reset_def);
                 if (node instanceof AST_Scope) node.variables.each(reset_def);
+                if (node.block_scope) node.block_scope.variables.each(reset_def);
                 if (node instanceof AST_SymbolRef) {
                     var d = node.definition();
                     d.references.push(node);
@@ -714,6 +726,16 @@ merge(Compressor.prototype, {
         return false;
     }
 
+    function is_undeclared_ref(node) {
+        return node instanceof AST_SymbolRef && node.definition().undeclared;
+    }
+
+    var global_names = makePredicate("Array Boolean clearInterval clearTimeout console Date decodeURI decodeURIComponent encodeURI encodeURIComponent Error escape eval EvalError Function isFinite isNaN JSON Math Number parseFloat parseInt RangeError ReferenceError RegExp Object setInterval setTimeout String SyntaxError TypeError unescape URIError");
+    AST_SymbolRef.DEFMETHOD("is_declared", function(compressor) {
+        return !this.definition().undeclared
+            || compressor.option("unsafe") && global_names(this.name);
+    });
+
     function tighten_body(statements, compressor) {
         var CHANGED, max_iter = 10;
         do {
@@ -785,7 +807,7 @@ merge(Compressor.prototype, {
                             || node instanceof AST_Debugger
                             || node instanceof AST_Destructuring
                             || node instanceof AST_IterationStatement && !(node instanceof AST_For)
-                            || node instanceof AST_SymbolRef && node.undeclared()
+                            || node instanceof AST_SymbolRef && !node.is_declared(compressor)
                             || node instanceof AST_Try
                             || node instanceof AST_With
                             || parent instanceof AST_For && node !== parent.init) {
@@ -817,6 +839,7 @@ merge(Compressor.prototype, {
                                     right: candidate.value
                                 });
                             }
+                            candidate.write_only = false;
                             return candidate;
                         }
                         // These node types have child nodes that execute sequentially,
@@ -904,7 +927,7 @@ merge(Compressor.prototype, {
                             }
                         } else {
                             var arg = iife.args[i];
-                            if (!arg) arg = make_node(AST_Undefined, sym);
+                            if (!arg) arg = make_node(AST_Undefined, sym).transform(compressor);
                             else if (has_overlapping_symbol(fn, arg)) arg = null;
                             if (arg) candidates.unshift(make_node(AST_VarDef, sym, {
                                 name: sym,
@@ -1389,12 +1412,12 @@ merge(Compressor.prototype, {
     // returns true if this node may be null, undefined or contain `AST_Accessor`
     (function(def) {
         AST_Node.DEFMETHOD("may_throw_on_access", function(compressor) {
-            var pure_getters = compressor.option("pure_getters");
-            return !pure_getters || this._throw_on_access(pure_getters);
+            return !compressor.option("pure_getters")
+                || this._dot_throw(compressor);
         });
 
-        function is_strict(pure_getters) {
-            return /strict/.test(pure_getters);
+        function is_strict(compressor) {
+            return /strict/.test(compressor.option("pure_getters"));
         }
 
         def(AST_Node, is_strict);
@@ -1402,49 +1425,55 @@ merge(Compressor.prototype, {
         def(AST_Undefined, return_true);
         def(AST_Constant, return_false);
         def(AST_Array, return_false);
-        def(AST_Object, function(pure_getters) {
-            if (!is_strict(pure_getters)) return false;
+        def(AST_Object, function(compressor) {
+            if (!is_strict(compressor)) return false;
             for (var i = this.properties.length; --i >=0;)
-                if (this.properties[i].value instanceof AST_Accessor) return true;
+                if (this.properties[i]._dot_throw(compressor)) return true;
             return false;
         });
+        def(AST_ObjectProperty, return_false);
+        def(AST_ObjectGetter, return_true);
+        def(AST_Expansion, function(compressor) {
+            return this.expression._dot_throw(compressor);
+        });
         def(AST_Function, return_false);
         def(AST_Arrow, return_false);
         def(AST_UnaryPostfix, return_false);
         def(AST_UnaryPrefix, function() {
             return this.operator == "void";
         });
-        def(AST_Binary, function(pure_getters) {
+        def(AST_Binary, function(compressor) {
             switch (this.operator) {
               case "&&":
-                return this.left._throw_on_access(pure_getters);
+                return this.left._dot_throw(compressor);
               case "||":
-                return this.left._throw_on_access(pure_getters)
-                    && this.right._throw_on_access(pure_getters);
+                return this.left._dot_throw(compressor)
+                    && this.right._dot_throw(compressor);
               default:
                 return false;
             }
         })
-        def(AST_Assign, function(pure_getters) {
+        def(AST_Assign, function(compressor) {
             return this.operator == "="
-                && this.right._throw_on_access(pure_getters);
+                && this.right._dot_throw(compressor);
         })
-        def(AST_Conditional, function(pure_getters) {
-            return this.consequent._throw_on_access(pure_getters)
-                || this.alternative._throw_on_access(pure_getters);
+        def(AST_Conditional, function(compressor) {
+            return this.consequent._dot_throw(compressor)
+                || this.alternative._dot_throw(compressor);
         })
-        def(AST_Sequence, function(pure_getters) {
-            return this.expressions[this.expressions.length - 1]._throw_on_access(pure_getters);
+        def(AST_Sequence, function(compressor) {
+            return this.expressions[this.expressions.length - 1]._dot_throw(compressor);
         });
-        def(AST_SymbolRef, function(pure_getters) {
+        def(AST_SymbolRef, function(compressor) {
             if (this.is_undefined) return true;
-            if (!is_strict(pure_getters)) return false;
+            if (!is_strict(compressor)) return false;
+            if (is_undeclared_ref(this) && this.is_declared(compressor)) return false;
             if (this.is_immutable()) return false;
             var fixed = this.fixed_value();
-            return !fixed || fixed._throw_on_access(pure_getters);
+            return !fixed || fixed._dot_throw(compressor);
         });
     })(function(node, func) {
-        node.DEFMETHOD("_throw_on_access", func);
+        node.DEFMETHOD("_dot_throw", func);
     });
 
     /* -----[ boolean/negation helpers ]----- */
@@ -1708,6 +1737,7 @@ merge(Compressor.prototype, {
                 var val = {};
                 for (var i = 0, len = this.properties.length; i < len; i++) {
                     var prop = this.properties[i];
+                    if (prop instanceof AST_Expansion) return this;
                     var key = prop.key;
                     if (key instanceof AST_Symbol) {
                         key = key.name;
@@ -1814,11 +1844,8 @@ merge(Compressor.prototype, {
         });
         var global_objs = {
             Array: Array,
-            Boolean: Boolean,
             Math: Math,
             Number: Number,
-            RegExp: RegExp,
-            Object: Object,
             String: String,
         };
         function convert_to_predicate(obj) {
@@ -1855,7 +1882,7 @@ merge(Compressor.prototype, {
                 }
                 var exp = this.expression;
                 var val;
-                if (exp instanceof AST_SymbolRef && exp.undeclared()) {
+                if (is_undeclared_ref(exp)) {
                     if (!(static_values[exp.name] || return_false)(key)) return this;
                     val = global_objs[exp.name];
                 } else {
@@ -1932,10 +1959,6 @@ merge(Compressor.prototype, {
                 "isFinite",
                 "isNaN",
             ],
-            Object: [
-                "keys",
-                "getOwnPropertyNames",
-            ],
             String: [
                 "fromCharCode",
             ],
@@ -1951,7 +1974,7 @@ merge(Compressor.prototype, {
                 }
                 var val;
                 var e = exp.expression;
-                if (e instanceof AST_SymbolRef && e.undeclared()) {
+                if (is_undeclared_ref(e)) {
                     if (!(static_fns[e.name] || return_false)(key)) return this;
                     val = global_objs[e.name];
                 } else {
@@ -2058,16 +2081,27 @@ merge(Compressor.prototype, {
         if (!compressor.option("side_effects")) return false;
         if (this.pure !== undefined) return this.pure;
         var pure = false;
-        var comments, last_comment;
+        var comments, pure_comment;
         if (this.start
             && (comments = this.start.comments_before)
             && comments.length
-            && /[@#]__PURE__/.test((last_comment = comments[comments.length - 1]).value)) {
-            pure = last_comment;
+            && (pure_comment = find_if(function (comment) {
+                return /[@#]__PURE__/.test(comment.value);
+            }, comments))) {
+            pure = pure_comment;
         }
         return this.pure = pure;
     });
 
+    var global_pure_fns = makePredicate("Boolean decodeURI decodeURIComponent Date encodeURI encodeURIComponent Error escape EvalError isFinite isNaN Number Object parseFloat parseInt RangeError ReferenceError String SyntaxError TypeError unescape URIError");
+    AST_Call.DEFMETHOD("is_expr_pure", function(compressor) {
+        if (compressor.option("unsafe")) {
+            var expr = this.expression;
+            if (is_undeclared_ref(expr) && global_pure_fns(expr.name)) return true;
+        }
+        return this.has_pure_annotation(compressor) || !compressor.pure_funcs(this);
+    });
+
     // determine if expression has side effects
     (function(def){
         def(AST_Node, return_true);
@@ -2077,7 +2111,7 @@ merge(Compressor.prototype, {
         def(AST_This, return_false);
 
         def(AST_Call, function(compressor){
-            if (!this.has_pure_annotation(compressor) && compressor.pure_funcs(this)) return true;
+            if (!this.is_expr_pure(compressor)) return true;
             for (var i = this.args.length; --i >= 0;) {
                 if (this.args[i].has_side_effects(compressor))
                     return true;
@@ -2139,7 +2173,7 @@ merge(Compressor.prototype, {
                 || this.expression.has_side_effects(compressor);
         });
         def(AST_SymbolRef, function(compressor){
-            return this.undeclared();
+            return !this.is_declared(compressor);
         });
         def(AST_SymbolDeclaration, return_false);
         def(AST_Object, function(compressor){
@@ -2271,7 +2305,12 @@ merge(Compressor.prototype, {
         if (self.uses_eval || self.uses_with) return;
         var drop_funcs = !(self instanceof AST_Toplevel) || compressor.toplevel.funcs;
         var drop_vars = !(self instanceof AST_Toplevel) || compressor.toplevel.vars;
-        var assign_as_unused = !/keep_assign/.test(compressor.option("unused"));
+        var assign_as_unused = /keep_assign/.test(compressor.option("unused")) ? return_false : function(node) {
+            if (node instanceof AST_Assign && (node.write_only || node.operator == "=")) {
+                return node.left;
+            }
+            if (node instanceof AST_Unary && node.write_only) return node.expression;
+        };
         var in_use = [];
         var in_use_ids = Object.create(null); // avoid expensive linear scans of in_use
         if (self instanceof AST_Toplevel && compressor.top_retain) {
@@ -2335,13 +2374,9 @@ merge(Compressor.prototype, {
                     });
                     return true;
                 }
-                if (assign_as_unused
-                    && node instanceof AST_Assign
-                    && node.operator == "="
-                    && node.left instanceof AST_SymbolRef
-                    && !is_ref_of(node.left, AST_SymbolBlockDeclaration)
-                    && scope === self) {
-                    node.right.walk(tw);
+                if (assign_as_unused(node) instanceof AST_SymbolRef && scope === self
+                    && !is_ref_of(node.left, AST_SymbolBlockDeclaration)) {
+                    if (node instanceof AST_Assign) node.right.walk(tw);
                     return true;
                 }
                 if (node instanceof AST_SymbolRef) {
@@ -2524,15 +2559,18 @@ merge(Compressor.prototype, {
                         });
                     }
                 }
-                if (assign_as_unused
-                    && node instanceof AST_Assign
-                    && node.operator == "="
-                    && node.left instanceof AST_SymbolRef) {
-                    var def = node.left.definition();
-                    if (!(def.id in in_use_ids)
+                if (drop_vars) {
+                    var def = assign_as_unused(node);
+                    if (def instanceof AST_SymbolRef
+                        && !((def = def.definition()).id in in_use_ids)
                         && (drop_vars || !def.global)
                         && self.variables.get(def.name) === def) {
-                        return maintain_this_binding(parent, node, node.right.transform(tt));
+                        if (node instanceof AST_Assign) {
+                            return maintain_this_binding(parent, node, node.right.transform(tt));
+                        }
+                        return make_node(AST_Number, node, {
+                            value: 0
+                        });
                     }
                 }
                 // certain combination of unused name + side effect leads to:
@@ -2543,17 +2581,18 @@ merge(Compressor.prototype, {
                 // We fix it at this stage by moving the `var` outside the `for`.
                 if (node instanceof AST_For) {
                     descend(node, this);
+                    var block;
                     if (node.init instanceof AST_BlockStatement) {
-                        var block = node.init;
+                        block = node.init;
                         node.init = block.body.pop();
                         block.body.push(node);
-                        return in_list ? MAP.splice(block.body) : block;
-                    } else if (node.init instanceof AST_SimpleStatement) {
+                    }
+                    if (node.init instanceof AST_SimpleStatement) {
                         node.init = node.init.body;
                     } else if (is_empty(node.init)) {
                         node.init = null;
                     }
-                    return node;
+                    return !block ? node : in_list ? MAP.splice(block.body) : block;
                 }
                 if (node instanceof AST_LabeledStatement && node.body instanceof AST_For) {
                     descend(node, this);
@@ -2749,7 +2788,7 @@ merge(Compressor.prototype, {
         def(AST_Constant, return_null);
         def(AST_This, return_null);
         def(AST_Call, function(compressor, first_in_statement){
-            if (!this.has_pure_annotation(compressor) && compressor.pure_funcs(this)) {
+            if (!this.is_expr_pure(compressor)) {
                 if (is_func_expr(this.expression)
                     && (!this.expression.name || !this.expression.name.definition().references.length)) {
                     var node = this.clone();
@@ -2785,7 +2824,10 @@ merge(Compressor.prototype, {
                 return make_sequence(this, [ left, right ]);
             }
         });
-        def(AST_Assign, return_this);
+        def(AST_Assign, function(compressor){
+            this.write_only = !this.left.has_side_effects(compressor);
+            return this;
+        });
         def(AST_Conditional, function(compressor){
             var consequent = this.consequent.drop_side_effect_free(compressor);
             var alternative = this.alternative.drop_side_effect_free(compressor);
@@ -2806,7 +2848,10 @@ merge(Compressor.prototype, {
             return node;
         });
         def(AST_Unary, function(compressor, first_in_statement){
-            if (unary_side_effects(this.operator)) return this;
+            if (unary_side_effects(this.operator)) {
+                this.write_only = !this.expression.has_side_effects(compressor);
+                return this;
+            }
             if (this.operator == "typeof" && this.expression instanceof AST_SymbolRef) return null;
             var expression = this.expression.drop_side_effect_free(compressor, first_in_statement);
             if (first_in_statement
@@ -2820,8 +2865,8 @@ merge(Compressor.prototype, {
             }
             return expression;
         });
-        def(AST_SymbolRef, function() {
-            return this.undeclared() ? this : null;
+        def(AST_SymbolRef, function(compressor) {
+            return this.is_declared(compressor) ? null : this;
         });
         def(AST_Object, function(compressor, first_in_statement){
             var values = trim(this.properties, compressor, first_in_statement);
@@ -3253,6 +3298,7 @@ merge(Compressor.prototype, {
                 });
                 a.push(var_);
             }
+            remove(def.name.definition().orig, def.name);
             return a;
         }, []);
         if (assignments.length == 0) return null;
@@ -3316,7 +3362,7 @@ merge(Compressor.prototype, {
             self.args.length = last;
         }
         if (compressor.option("unsafe")) {
-            if (exp instanceof AST_SymbolRef && exp.undeclared()) {
+            if (is_undeclared_ref(exp)) {
                 switch (exp.name) {
                   case "Array":
                     if (self.args.length != 1) {
@@ -3447,8 +3493,7 @@ merge(Compressor.prototype, {
             }
         }
         if (compressor.option("unsafe_Func")
-            && exp instanceof AST_SymbolRef
-            && exp.undeclared()
+            && is_undeclared_ref(exp)
             && exp.name == "Function") {
             // new Function() => function(){}
             if (self.args.length == 0) return make_node(AST_Function, self, {
@@ -3581,9 +3626,7 @@ merge(Compressor.prototype, {
                 while (name.expression) {
                     name = name.expression;
                 }
-                if (name instanceof AST_SymbolRef
-                    && name.name == "console"
-                    && name.undeclared()) {
+                if (is_undeclared_ref(name) && name.name == "console") {
                     return make_node(AST_Undefined, self).optimize(compressor);
                 }
             }
@@ -3604,7 +3647,7 @@ merge(Compressor.prototype, {
     OPT(AST_New, function(self, compressor){
         if (compressor.option("unsafe")) {
             var exp = self.expression;
-            if (exp instanceof AST_SymbolRef && exp.undeclared()) {
+            if (is_undeclared_ref(exp)) {
                 switch (exp.name) {
                   case "Object":
                   case "RegExp":
@@ -3681,6 +3724,8 @@ merge(Compressor.prototype, {
                                 operator: car.operator,
                                 expression: left
                             });
+                        } else {
+                            car.write_only = false;
                         }
                         if (parent) {
                             parent[field] = car;
@@ -3896,7 +3941,7 @@ merge(Compressor.prototype, {
                 && self.right instanceof AST_UnaryPrefix
                 && self.right.operator == "typeof") {
                 var expr = self.right.expression;
-                if (expr instanceof AST_SymbolRef ? !expr.undeclared()
+                if (expr instanceof AST_SymbolRef ? expr.is_declared(compressor)
                     : !(expr instanceof AST_PropAccess && compressor.option("ie8"))) {
                     self.right = expr;
                     self.left = make_node(AST_Undefined, self.left).optimize(compressor);
@@ -4226,7 +4271,7 @@ merge(Compressor.prototype, {
         }
         // testing against !self.scope.uses_with first is an optimization
         if (!compressor.option("ie8")
-            && self.undeclared()
+            && is_undeclared_ref(self)
             && (!self.scope.uses_with || !compressor.find_parent(AST_With))) {
             switch (self.name) {
               case "undefined":
@@ -4468,6 +4513,8 @@ merge(Compressor.prototype, {
             && alternative.TYPE === consequent.TYPE
             && consequent.args.length == 1
             && alternative.args.length == 1
+            && !(consequent.args[0] instanceof AST_Expansion)
+            && !(alternative.args[0] instanceof AST_Expansion)
             && consequent.expression.equivalent_to(alternative.expression)
             && !consequent.expression.has_side_effects(compressor)) {
             consequent.args[0] = make_node(AST_Conditional, self, {
@@ -4598,7 +4645,7 @@ merge(Compressor.prototype, {
         var prop = self.property;
         if (prop instanceof AST_String && compressor.option("properties")) {
             prop = prop.getValue();
-            if (RESERVED_WORDS(prop) ? !compressor.option("ie8") : is_identifier_string(prop)) {
+            if (is_identifier_string(prop)) {
                 return make_node(AST_Dot, self, {
                     expression : self.expression,
                     property   : prop
@@ -4635,20 +4682,11 @@ merge(Compressor.prototype, {
         if (def) {
             return def.optimize(compressor);
         }
-        var prop = self.property;
-        if (RESERVED_WORDS(prop) && compressor.option("ie8")) {
-            return make_node(AST_Sub, self, {
-                expression : self.expression,
-                property   : make_node(AST_String, self, {
-                    value: prop
-                })
-            }).optimize(compressor);
-        }
         if (compressor.option("unsafe") && self.expression instanceof AST_Object) {
             var values = self.expression.properties;
             for (var i = values.length; --i >= 0;) {
                 var key = values[i].key;
-                if ((key instanceof AST_SymbolMethod ? key.name : key) === prop) {
+                if ((key instanceof AST_SymbolMethod ? key.name : key) === self.property) {
                     var value = values[i].value;
                     if (key instanceof AST_SymbolMethod) {
                         if (values[i].is_generator) break;
@@ -4667,7 +4705,7 @@ merge(Compressor.prototype, {
             && self.expression instanceof AST_Dot
             && self.expression.property == "prototype") {
             var exp = self.expression.expression;
-            if (exp instanceof AST_SymbolRef && exp.undeclared()) switch (exp.name) {
+            if (is_undeclared_ref(exp)) switch (exp.name) {
               case "Array":
                 self.expression = make_node(AST_Array, self.expression, {
                     elements: []
@@ -4726,7 +4764,7 @@ merge(Compressor.prototype, {
 
     OPT(AST_Function, function(self, compressor){
         tighten_body(self.body, compressor);
-        if (compressor.option("arrows")
+        if (compressor.option("unsafe_arrows")
             && compressor.option("ecma") >= 6
             && !self.name
             && !self.is_generator
@@ -4808,7 +4846,8 @@ merge(Compressor.prototype, {
             arrow.is_generator = self.is_generator;
             return make_node(AST_ObjectKeyVal, self, {
                 key: self.key instanceof AST_SymbolMethod ? self.key.name : self.key,
-                value: arrow
+                value: arrow,
+                quote: self.quote,
             });
         }
         return self;
@@ -4834,6 +4873,7 @@ merge(Compressor.prototype, {
                         name: key,
                     }),
                     value: make_node(AST_Accessor, value, value),
+                    quote: self.quote,
                 });
             }
         }

lib/minify.js

@@ -70,6 +70,7 @@ function minify(files, options) {
         set_shorthand("keep_fnames", options, [ "compress", "mangle" ]);
         set_shorthand("toplevel", options, [ "compress", "mangle" ]);
         set_shorthand("warnings", options, [ "compress" ]);
+        var quoted_props;
         if (options.mangle) {
             options.mangle = defaults(options.mangle, {
                 cache: options.nameCache && (options.nameCache.vars || {}),
@@ -82,11 +83,16 @@ function minify(files, options) {
                 safari10: false,
                 toplevel: false,
             }, true);
-            if (options.nameCache && options.mangle.properties) {
+            if (options.mangle.properties) {
                 if (typeof options.mangle.properties != "object") {
                     options.mangle.properties = {};
                 }
-                if (!("cache" in options.mangle.properties)) {
+                if (options.mangle.properties.keep_quoted) {
+                    quoted_props = options.mangle.properties.reserved;
+                    if (!Array.isArray(quoted_props)) quoted_props = [];
+                    options.mangle.properties.reserved = quoted_props;
+                }
+                if (options.nameCache && !("cache" in options.mangle.properties)) {
                     options.mangle.properties.cache = options.nameCache.props || {};
                 }
             }
@@ -129,6 +135,9 @@ function minify(files, options) {
             }
             toplevel = options.parse.toplevel;
         }
+        if (quoted_props) {
+            reserve_quoted_keys(toplevel, quoted_props);
+        }
         if (options.wrap) {
             toplevel = toplevel.wrap_commonjs(options.wrap);
         }

lib/output.js

@@ -54,7 +54,6 @@ function OutputStream(options) {
 
     options = defaults(options, {
         ascii_only       : false,
-        ascii_identifiers: undefined,
         beautify         : false,
         bracketize       : false,
         comments         : false,
@@ -78,9 +77,6 @@ function OutputStream(options) {
         wrap_iife        : false,
     }, true);
 
-    if (typeof options.ascii_identifiers === 'undefined')
-        options.ascii_identifiers = options.ascii_only;
-
     if (options.shorthand === undefined)
         options.shorthand = options.ecma > 5;
 
@@ -118,20 +114,16 @@ function OutputStream(options) {
     var current_pos = 0;
     var OUTPUT = "";
 
-    function to_ascii(str, identifier) {
-        return str.replace(/[\ud800-\udbff][\udc00-\udfff]|[\u0000-\u001f\u007f-\uffff]/g, function(ch) {
-            var code = get_full_char_code(ch, 0).toString(16);
-
-            if ((identifier && code.length === 1 && options.ecma >= 6) || code.length > 4) {
-                if (options.ecma < 6) {
-                    if (identifier) {
-                        return ch; // no \u{} support
-                    }
-                    return "\\u" + ch.charCodeAt(0).toString(16) + "\\u"
-                        + ch.charCodeAt(1).toString(16);
-                }
+    var to_utf8 = options.ascii_only ? function(str, identifier) {
+        if (options.ecma >= 6) {
+            str = str.replace(/[\ud800-\udbff][\udc00-\udfff]/g, function(ch) {
+                var code = get_full_char_code(ch, 0).toString(16);
                 return "\\u{" + code + "}";
-            } else if (code.length <= 2 && !identifier) {
+            });
+        }
+        return str.replace(/[\u0000-\u001f\u007f-\uffff]/g, function(ch) {
+            var code = ch.charCodeAt(0).toString(16);
+            if (code.length <= 2 && !identifier) {
                 while (code.length < 2) code = "0" + code;
                 return "\\x" + code;
             } else {
@@ -139,6 +131,12 @@ function OutputStream(options) {
                 return "\\u" + code;
             }
         });
+    } : function(str) {
+        return str.replace(/[\ud800-\udbff](?![\udc00-\udfff])/g, function(ch) {
+            return "\\u" + ch.charCodeAt(0).toString(16);
+        }).replace(/(^|[^\ud800-\udbff])([\udc00-\udfff])/g, function(match, prefix, ch) {
+            return prefix + "\\u" + ch.charCodeAt(0).toString(16);
+        });
     };
 
     function make_string(str, quote) {
@@ -159,7 +157,7 @@ function OutputStream(options) {
               case "\u2029": return "\\u2029";
               case "\ufeff": return "\\ufeff";
               case "\0":
-                  return /[0-7]/.test(get_full_char(str, i+1)) ? "\\x00" : "\\0";
+                  return /[0-9]/.test(get_full_char(str, i+1)) ? "\\x00" : "\\0";
             }
             return s;
         });
@@ -172,7 +170,7 @@ function OutputStream(options) {
         function quote_template() {
             return '`' + str.replace(/`/g, '\\`') + '`';
         }
-        if (options.ascii_only) str = to_ascii(str);
+        str = to_utf8(str);
         if (quote === "`") return quote_template();
         switch (options.quote_style) {
           case 1:
@@ -198,8 +196,7 @@ function OutputStream(options) {
 
     function make_name(name) {
         name = name.toString();
-        if (options.ascii_identifiers)
-            name = to_ascii(name, true);
+        name = to_utf8(name, true);
         return name;
     };
 
@@ -461,7 +458,7 @@ function OutputStream(options) {
         last            : function() { return last },
         semicolon       : semicolon,
         force_semicolon : force_semicolon,
-        to_ascii        : to_ascii,
+        to_utf8         : to_utf8,
         print_name      : function(name) { print(make_name(name)) },
         print_string    : function(str, quote, escape_directive) {
             var encoded = encode_string(str, quote);
@@ -692,6 +689,7 @@ function OutputStream(options) {
                                                                * ==> 20 (side effect, set a := 10 and b := 20) */
             || p instanceof AST_Arrow                         // x => (x, x)
             || p instanceof AST_DefaultAssign                 // x => (x = (0, function(){}))
+            || p instanceof AST_Expansion                     // [...(a, b)]
         ;
     });
 
@@ -1400,6 +1398,9 @@ function OutputStream(options) {
         self.expression.print(output);
         if (self instanceof AST_New && !need_constructor_parens(self, output))
             return;
+        if (self.expression instanceof AST_Lambda) {
+            output.add_mapping(self.start);
+        }
         output.with_parens(function(){
             self.args.forEach(function(expr, i){
                 if (i) output.comma();
@@ -1439,15 +1440,23 @@ function OutputStream(options) {
     DEFPRINT(AST_Dot, function(self, output){
         var expr = self.expression;
         expr.print(output);
-        if (expr instanceof AST_Number && expr.getValue() >= 0) {
-            if (!/[xa-f.)]/i.test(output.last())) {
-                output.print(".");
+        var prop = self.property;
+        if (output.option("ie8") && RESERVED_WORDS(prop)) {
+            output.print("[");
+            output.add_mapping(self.end);
+            output.print_string(prop);
+            output.print("]");
+        } else {
+            if (expr instanceof AST_Number && expr.getValue() >= 0) {
+                if (!/[xa-f.)]/i.test(output.last())) {
+                    output.print(".");
+                }
             }
+            output.print(".");
+            // the name after dot would be mapped about here.
+            output.add_mapping(self.end);
+            output.print_name(prop);
         }
-        output.print(".");
-        // the name after dot would be mapped about here.
-        output.add_mapping(self.end);
-        output.print_name(self.property);
     });
     DEFPRINT(AST_Sub, function(self, output){
         self.expression.print(output);
@@ -1702,9 +1711,7 @@ function OutputStream(options) {
         if (regexp.raw_source) {
             str = "/" + regexp.raw_source + str.slice(str.lastIndexOf("/"));
         }
-        if (output.option("ascii_only")) {
-            str = output.to_ascii(str);
-        }
+        str = output.to_utf8(str);
         output.print(str);
         var p = output.parent();
         if (p instanceof AST_Binary && /^in/.test(p.operator) && p.left === self)

lib/parse.js

@@ -1522,7 +1522,7 @@ function parse($TEXT, options) {
                 }
                 if (is_expand) {
                     if (!is("punc", "]")) {
-                        unexpected(); // Must be last element
+                        croak("Rest element must be last element");
                     }
                     elements[elements.length - 1] = new AST_Expansion({
                         start: expand_token,
@@ -1547,18 +1547,33 @@ function parse($TEXT, options) {
                 } else {
                     expect(",");
                 }
+                if (is("expand", "...")) {
+                    is_expand = true;
+                    expand_token = S.token;
+                    used_parameters.mark_spread(S.token);
+                    next();
+                }
                 if (is("name") && (is_token(peek(), "punc") || is_token(peek(), "operator")) && [",", "}", "="].indexOf(peek().value) !== -1) {
                     used_parameters.add_parameter(S.token);
-                    elements.push(new AST_ObjectKeyVal({
-                        start: prev(),
-                        key: S.token.value,
-                        value: new symbol_type({
-                            start: S.token,
-                            name: S.token.value,
-                            end: S.token
-                        }),
-                        end: prev()
-                    }));
+                    var value = new symbol_type({
+                        start: S.token,
+                        name: S.token.value,
+                        end: S.token,
+                    });
+                    if (is_expand) {
+                        elements.push(new AST_Expansion({
+                            start: expand_token,
+                            expression: value,
+                            end: value.end,
+                        }));
+                    } else {
+                        elements.push(new AST_ObjectKeyVal({
+                            start: prev(),
+                            key: S.token.value,
+                            value: value,
+                            end: value.end,
+                        }));
+                    }
                     next();
                 } else if (is("punc", "}")) {
                     continue; // Allow trailing hole
@@ -1589,7 +1604,12 @@ function parse($TEXT, options) {
                         }));
                     }
                 }
-                if (is("operator", "=")) {
+                if (is_expand) {
+                    if (!is("punc", "}")) {
+                        croak("Rest element must be last element");
+                    }
+                }
+                else if (is("operator", "=")) {
                     used_parameters.mark_default_assignment(S.token);
                     next();
                     elements[elements.length - 1].value = new AST_DefaultAssign({
@@ -2143,7 +2163,18 @@ function parse($TEXT, options) {
             if (!options.strict && is("punc", "}"))
                 // allow trailing comma
                 break;
+
             start = S.token;
+            if (start.type == "expand") {
+                next();
+                a.push(new AST_Expansion({
+                    start: start,
+                    expression: expression(false),
+                    end: prev(),
+                }));
+                continue;
+            }
+
             var name = as_property_name();
             var value;
 

lib/propmangle.js

@@ -85,6 +85,36 @@ function find_builtins(reserved) {
     }
 }
 
+function reserve_quoted_keys(ast, reserved) {
+    function add(name) {
+        push_uniq(reserved, name);
+    }
+
+    ast.walk(new TreeWalker(function(node) {
+        if (node instanceof AST_ObjectKeyVal && node.quote) {
+            add(node.key);
+        } else if (node instanceof AST_ObjectProperty && node.quote) {
+            add(node.key.name);
+        } else if (node instanceof AST_Sub) {
+            addStrings(node.property, add);
+        }
+    }));
+}
+
+function addStrings(node, add) {
+    node.walk(new TreeWalker(function(node) {
+        if (node instanceof AST_Sequence) {
+            addStrings(node.expressions[node.expressions.length - 1], add);
+        } else if (node instanceof AST_String) {
+            add(node.value);
+        } else if (node instanceof AST_Conditional) {
+            addStrings(node.consequent, add);
+            addStrings(node.alternative, add);
+        }
+        return true;
+    }));
+}
+
 function mangle_properties(ast, options) {
     options = defaults(options, {
         builtins: false,
@@ -94,7 +124,7 @@ function mangle_properties(ast, options) {
         only_cache: false,
         regex: null,
         reserved: null,
-    });
+    }, true);
 
     var reserved = options.reserved;
     if (!Array.isArray(reserved)) reserved = [];
@@ -109,7 +139,6 @@ function mangle_properties(ast, options) {
     }
 
     var regex = options.regex;
-    var keep_quoted = options.keep_quoted;
 
     // note debug is either false (disabled), or a string of the debug suffix to use (enabled).
     // note debug may be enabled as an empty string, which is falsey. Also treat passing 'true'
@@ -122,12 +151,11 @@ function mangle_properties(ast, options) {
 
     var names_to_mangle = [];
     var unmangleable = [];
-    var to_keep = {};
 
     // step 1: find candidates to mangle
     ast.walk(new TreeWalker(function(node){
         if (node instanceof AST_ObjectKeyVal) {
-            add(node.key, keep_quoted && node.quote);
+            add(node.key);
         }
         else if (node instanceof AST_ObjectProperty) {
             // setter or getter, since KeyVal is handled above
@@ -137,18 +165,14 @@ function mangle_properties(ast, options) {
             add(node.property);
         }
         else if (node instanceof AST_Sub) {
-            addStrings(node.property, keep_quoted);
-        }
-        else if (node instanceof AST_ConciseMethod) {
-            add(node.name.name);
+            addStrings(node.property, add);
         }
     }));
 
     // step 2: transform the tree, renaming properties
     return ast.transform(new TreeTransformer(function(node){
         if (node instanceof AST_ObjectKeyVal) {
-            if (!(keep_quoted && node.quote))
-                node.key = mangle(node.key);
+            node.key = mangle(node.key);
         }
         else if (node instanceof AST_ObjectProperty) {
             // setter or getter
@@ -157,27 +181,9 @@ function mangle_properties(ast, options) {
         else if (node instanceof AST_Dot) {
             node.property = mangle(node.property);
         }
-        else if (node instanceof AST_Sub) {
-            if (!keep_quoted)
-                node.property = mangleStrings(node.property);
+        else if (!options.keep_quoted && node instanceof AST_Sub) {
+            node.property = mangleStrings(node.property);
         }
-        else if (node instanceof AST_ConciseMethod) {
-            if (should_mangle(node.name.name)) {
-                node.name.name = mangle(node.name.name);
-            }
-        }
-        // else if (node instanceof AST_String) {
-        //     if (should_mangle(node.value)) {
-        //         AST_Node.warn(
-        //             "Found \"{prop}\" property candidate for mangling in an arbitrary string [{file}:{line},{col}]", {
-        //                 file : node.start.file,
-        //                 line : node.start.line,
-        //                 col  : node.start.col,
-        //                 prop : node.value
-        //             }
-        //         );
-        //     }
-        // }
     }));
 
     // only function declarations after this line
@@ -193,19 +199,13 @@ function mangle_properties(ast, options) {
     }
 
     function should_mangle(name) {
-        if (keep_quoted && name in to_keep) return false;
         if (regex && !regex.test(name)) return false;
         if (reserved.indexOf(name) >= 0) return false;
         return cache.props.has(name)
             || names_to_mangle.indexOf(name) >= 0;
     }
 
-    function add(name, keep) {
-        if (keep) {
-            to_keep[name] = true;
-            return;
-        }
-
+    function add(name) {
         if (can_mangle(name))
             push_uniq(names_to_mangle, name);
 
@@ -225,19 +225,16 @@ function mangle_properties(ast, options) {
                 // debug mode: use a prefix and suffix to preserve readability, e.g. o.foo -> o._$foo$NNN_.
                 var debug_mangled = "_$" + name + "$" + debug_name_suffix + "_";
 
-                if (can_mangle(debug_mangled) && !(keep_quoted && debug_mangled in to_keep)) {
+                if (can_mangle(debug_mangled)) {
                     mangled = debug_mangled;
                 }
             }
 
             // either debug mode is off, or it is on and we could not use the mangled name
             if (!mangled) {
-                // Note: `can_mangle()` does not check if the name collides with the `to_keep` set
-                // (filled with quoted properties when `keep_quoted` is set). Make sure we add this
-                // check so we don't collide with a quoted name.
                 do {
                     mangled = base54(++cache.cname);
-                } while (!can_mangle(mangled) || keep_quoted && mangled in to_keep);
+                } while (!can_mangle(mangled));
             }
 
             cache.props.set(name, mangled);
@@ -245,32 +242,6 @@ function mangle_properties(ast, options) {
         return mangled;
     }
 
-    function addStrings(node, keep) {
-        var out = {};
-        try {
-            (function walk(node){
-                node.walk(new TreeWalker(function(node){
-                    if (node instanceof AST_Sequence) {
-                        walk(node.expressions[node.expressions.length - 1]);
-                        return true;
-                    }
-                    if (node instanceof AST_String) {
-                        add(node.value, keep);
-                        return true;
-                    }
-                    if (node instanceof AST_Conditional) {
-                        walk(node.consequent);
-                        walk(node.alternative);
-                        return true;
-                    }
-                    throw out;
-                }));
-            })(node);
-        } catch(ex) {
-            if (ex !== out) throw ex;
-        }
-    }
-
     function mangleStrings(node) {
         return node.transform(new TreeTransformer(function(node){
             if (node instanceof AST_Sequence) {

lib/scope.js

@@ -116,7 +116,7 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options){
     var tw = new TreeWalker(function(node, descend){
         if (node.is_block_scope()) {
             var save_scope = scope;
-            scope = new AST_Scope(node);
+            node.block_scope = scope = new AST_Scope(node);
             scope.init_scope_vars(save_scope);
             if (!(node instanceof AST_Scope)) {
                 scope.uses_with = save_scope.uses_with;
@@ -203,6 +203,21 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options){
             || node instanceof AST_SymbolLet
             || node instanceof AST_SymbolConst) {
             var def = ((node instanceof AST_SymbolBlockDeclaration) ? scope : defun).def_variable(node);
+            if (!all(def.orig, function(sym) {
+                if (sym === node) return true;
+                if (node instanceof AST_SymbolBlockDeclaration) {
+                    return sym instanceof AST_SymbolLambda;
+                }
+                return !(sym instanceof AST_SymbolLet || sym instanceof AST_SymbolConst);
+            })) {
+                js_error(
+                    node.name + " redeclared",
+                    node.start.file,
+                    node.start.line,
+                    node.start.col,
+                    node.start.pos
+                );
+            }
             if (!(node instanceof AST_SymbolFunarg)) mark_export(def, 2);
             def.destructuring = in_destructuring;
             if (defun !== scope) {
@@ -300,6 +315,7 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options){
                     ref.reference(options);
                 });
                 node.thedef = def;
+                node.reference(options);
                 return true;
             }
         }));
@@ -357,7 +373,7 @@ AST_IterationStatement.DEFMETHOD("is_block_scope", return_true);
 AST_Lambda.DEFMETHOD("init_scope_vars", function(){
     AST_Scope.prototype.init_scope_vars.apply(this, arguments);
     this.uses_arguments = false;
-    this.def_variable(new AST_SymbolConst({
+    this.def_variable(new AST_SymbolFunarg({
         name: "arguments",
         start: this.start,
         end: this.end
@@ -461,14 +477,6 @@ AST_Symbol.DEFMETHOD("unreferenced", function(){
         && !(this.scope.uses_eval || this.scope.uses_with);
 });
 
-AST_Symbol.DEFMETHOD("undeclared", function(){
-    return this.definition().undeclared;
-});
-
-AST_LabelRef.DEFMETHOD("undeclared", return_false);
-
-AST_Label.DEFMETHOD("undeclared", return_false);
-
 AST_Symbol.DEFMETHOD("definition", function(){
     return this.thedef;
 });

package.json

@@ -1,17 +1,17 @@
 {
   "name": "uglify-es",
-  "description": "JavaScript parser, mangler/compressor and beautifier toolkit",
+  "description": "JavaScript parser, mangler/compressor and beautifier toolkit for ES6+",
   "homepage": "https://github.com/mishoo/UglifyJS2/tree/harmony",
   "author": "Mihai Bazon <mihai.bazon@gmail.com> (http://lisperator.net/)",
   "license": "BSD-2-Clause",
-  "version": "3.0.24",
+  "version": "3.1.0",
   "engines": {
     "node": ">=0.8.0"
   },
   "maintainers": [
     "Mihai Bazon <mihai.bazon@gmail.com> (http://lisperator.net/)"
   ],
-  "repository": "https://github.com/mishoo/UglifyJS2/tree/harmony",
+  "repository": "git+https://github.com/mishoo/UglifyJS2.git#harmony",
   "bugs": {
     "url": "https://github.com/mishoo/UglifyJS2/issues"
   },
@@ -26,25 +26,29 @@
     "LICENSE"
   ],
   "dependencies": {
-    "commander": "~2.9.0",
+    "commander": "~2.11.0",
     "source-map": "~0.5.1"
   },
   "devDependencies": {
-    "acorn": "~5.0.3",
-    "mocha": "~2.3.4",
-    "semver": "~5.3.0"
+    "acorn": "~5.1.1",
+    "mocha": "~3.5.1",
+    "semver": "~5.4.1"
   },
   "scripts": {
     "test": "node test/run-tests.js"
   },
   "keywords": [
     "uglify",
-    "uglify-js",
     "uglify-es",
+    "uglify-js",
     "minify",
     "minifier",
+    "javascript",
+    "ecmascript",
     "es5",
     "es6",
+    "es7",
+    "es8",
     "es2015",
     "es2016",
     "es2017",

test/benchmark.js

@@ -6,6 +6,7 @@
 var createHash = require("crypto").createHash;
 var fetch = require("./fetch");
 var fork = require("child_process").fork;
+var zlib = require("zlib");
 var args = process.argv.slice(2);
 if (!args.length) {
     args.push("-mc");
@@ -33,6 +34,7 @@ function done() {
             console.log(info.log);
             console.log("Original:", info.input, "bytes");
             console.log("Uglified:", info.output, "bytes");
+            console.log("GZipped: ", info.gzip, "bytes");
             console.log("SHA1 sum:", info.sha1);
             if (info.code) {
                 failures.push(url);
@@ -51,6 +53,7 @@ urls.forEach(function(url) {
     results[url] = {
         input: 0,
         output: 0,
+        gzip: 0,
         log: ""
     };
     fetch(url, function(err, res) {
@@ -61,6 +64,10 @@ urls.forEach(function(url) {
         }).pipe(uglifyjs.stdin);
         uglifyjs.stdout.on("data", function(data) {
             results[url].output += data.length;
+        }).pipe(zlib.createGzip({
+            level: zlib.Z_BEST_COMPRESSION
+        })).on("data", function(data) {
+            results[url].gzip += data.length;
         }).pipe(createHash("sha1")).on("data", function(data) {
             results[url].sha1 = data.toString("hex");
             done();

test/compress/arrow.js

@@ -213,7 +213,7 @@ no_leading_parentheses: {
 
 async_identifiers: {
     options = {
-        arrows: true,
+        unsafe_arrows: true,
         ecma: 6,
     }
     input: {
@@ -237,7 +237,7 @@ async_identifiers: {
 
 async_function_expression: {
     options = {
-        arrows: true,
+        unsafe_arrows: true,
         ecma: 6,
         evaluate: true,
         side_effects: true,
@@ -262,7 +262,7 @@ async_function_expression: {
 
 issue_27: {
     options = {
-        arrows: true,
+        unsafe_arrows: true,
         collapse_vars: true,
         ecma: 6,
         unused: true,
@@ -283,7 +283,7 @@ issue_27: {
 
 issue_2105_1: {
     options = {
-        arrows: true,
+        unsafe_arrows: true,
         collapse_vars: true,
         ecma: 6,
         inline: true,
@@ -501,7 +501,7 @@ issue_485_crashing_1530: {
 
 issue_2084: {
     options = {
-        arrows: true,
+        unsafe_arrows: true,
         collapse_vars: true,
         conditionals: true,
         ecma: 6,
@@ -577,6 +577,7 @@ concise_methods_with_computed_property2: {
 async_object_literal: {
     options = {
         arrows: true,
+        unsafe_arrows: true,
         ecma: 6,
         evaluate: true,
     }
@@ -597,3 +598,35 @@ async_object_literal: {
         };
     }
 }
+
+issue_2271: {
+    options = {
+        arrows: true,
+        ecma: 6,
+        evaluate: true,
+        unsafe_arrows: false,
+    }
+    input: {
+        var Foo = function() {};
+        Foo.prototype.set = function(value) {
+            this.value = value;
+            return this;
+        }
+        Foo.prototype.print = function() {
+            console.log(this.value);
+        }
+        new Foo().set("PASS").print();
+    }
+    expect: {
+        var Foo = function() {};
+        Foo.prototype.set = function(value) {
+            this.value = value;
+            return this;
+        }
+        Foo.prototype.print = function() {
+            console.log(this.value);
+        }
+        new Foo().set("PASS").print();
+    }
+    expect_stdout: "PASS"
+}

test/compress/ascii.js

@@ -13,7 +13,7 @@ ascii_only_true: {
                    "\x20\x21\x22\x23 ... \x7d\x7e\x7f\x80\x81 ... \xfe\xff\u0fff\uffff";
         }
     }
-    expect_exact: 'function f(){return"\\x000\\x001\\x007\\08\\0"+"\\0\\x01\\x02\\x03\\x04\\x05\\x06\\x07\\b\\t\\n\\v\\f\\r\\x0e\\x0f"+"\\x10\\x11\\x12\\x13\\x14\\x15\\x16\\x17\\x18\\x19\\x1a\\x1b\\x1c\\x1d\\x1e\\x1f"+\' !"# ... }~\\x7f\\x80\\x81 ... \\xfe\\xff\\u0fff\\uffff\'}'
+    expect_exact: 'function f(){return"\\x000\\x001\\x007\\x008\\0"+"\\0\\x01\\x02\\x03\\x04\\x05\\x06\\x07\\b\\t\\n\\v\\f\\r\\x0e\\x0f"+"\\x10\\x11\\x12\\x13\\x14\\x15\\x16\\x17\\x18\\x19\\x1a\\x1b\\x1c\\x1d\\x1e\\x1f"+\' !"# ... }~\\x7f\\x80\\x81 ... \\xfe\\xff\\u0fff\\uffff\'}'
 }
 
 ascii_only_false: {
@@ -31,5 +31,5 @@ ascii_only_false: {
                    "\x20\x21\x22\x23 ... \x7d\x7e\x7f\x80\x81 ... \xfe\xff\u0fff\uffff";
         }
     }
-    expect_exact: 'function f(){return"\\x000\\x001\\x007\\08\\0"+"\\0\x01\x02\x03\x04\x05\x06\x07\\b\\t\\n\\v\\f\\r\x0e\x0f"+"\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f"+\' !"# ... }~\x7f\x80\x81 ... \xfe\xff\u0fff\uffff\'}'
+    expect_exact: 'function f(){return"\\x000\\x001\\x007\\x008\\0"+"\\0\x01\x02\x03\x04\x05\x06\x07\\b\\t\\n\\v\\f\\r\x0e\x0f"+"\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f"+\' !"# ... }~\x7f\x80\x81 ... \xfe\xff\u0fff\uffff\'}'
 }

test/compress/collapse_vars.js

@@ -863,7 +863,7 @@ collapse_vars_unary: {
     input: {
         function f0(o, p) {
             var x = o[p];
-            delete x;
+            return delete x;
         }
         function f1(n) {
             var k = !!n;
@@ -893,7 +893,7 @@ collapse_vars_unary: {
     expect: {
         function f0(o, p) {
             var x = o[p];
-            delete x;
+            return delete x;
         }
         function f1(n) {
             return n > +!!n
@@ -2548,3 +2548,113 @@ duplicate_argname: {
     }
     expect_stdout: "PASS"
 }
+
+issue_2250_1: {
+    options = {
+        collapse_vars: true,
+        conditionals: true,
+        reduce_vars: true,
+    }
+    input: {
+        function f(x) {
+            if (x) {
+                const a = foo();
+                x(a);
+            }
+        }
+        function g(x) {
+            if (x) {
+                let a = foo();
+                x(a);
+            }
+        }
+        function h(x) {
+            if (x) {
+                var a = foo();
+                x(a);
+            }
+        }
+    }
+    expect: {
+        function f(x) {
+            x && x(foo());
+        }
+        function g(x) {
+            x && x(foo());
+        }
+        function h(x) {
+            x && x(foo());
+        }
+    }
+}
+
+issue_2250_2: {
+    options = {
+        collapse_vars: true,
+        passes: 2,
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+    }
+    input: {
+        {
+            const foo = function(){};
+            foo(bar());
+        }
+        {
+            let foo = function(){};
+            foo(bar());
+        }
+        {
+            var foo = function(){};
+            foo(bar());
+        }
+    }
+    expect: {
+        bar();
+        bar();
+        bar();
+    }
+}
+
+issue_2298: {
+    options = {
+        collapse_vars: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        !function() {
+            function f() {
+                var a = undefined;
+                var undefined = a++;
+                try {
+                    !function g(b) {
+                        b[1] = "foo";
+                    }();
+                    console.log("FAIL");
+                } catch (e) {
+                    console.log("PASS");
+                }
+            }
+            f();
+        }();
+    }
+    expect: {
+        !function() {
+            (function() {
+                var a = undefined;
+                var undefined = a++;
+                try {
+                    !function(b) {
+                        (void 0)[1] = "foo";
+                    }();
+                    console.log("FAIL");
+                } catch (e) {
+                    console.log("PASS");
+                }
+            })();
+        }();
+    }
+    expect_stdout: "PASS"
+}

test/compress/concat-strings.js

@@ -21,7 +21,7 @@ concat_1: {
         var c = 1 + x() + 2 + "boo";
         var d = 1 + x() + 2 + 3 + "boo";
         var e = 1 + x() + 2 + "X3boo";
-        var f = "\x00360\08\0";
+        var f = "\x00360\x008\0";
     }
 }
 

test/compress/dead-code.js

@@ -377,3 +377,186 @@ accessor: {
     }
     expect: {}
 }
+
+issue_2233_1: {
+    options = {
+        pure_getters: "strict",
+        side_effects: true,
+        unsafe: true,
+    }
+    input: {
+        Array.isArray;
+        Boolean;
+        console.log;
+        Date;
+        decodeURI;
+        decodeURIComponent;
+        encodeURI;
+        encodeURIComponent;
+        Error.name;
+        escape;
+        eval;
+        EvalError;
+        Function.length;
+        isFinite;
+        isNaN;
+        JSON;
+        Math.random;
+        Number.isNaN;
+        parseFloat;
+        parseInt;
+        RegExp;
+        Object.defineProperty;
+        String.fromCharCode;
+        RangeError;
+        ReferenceError;
+        SyntaxError;
+        TypeError;
+        unescape;
+        URIError;
+    }
+    expect: {}
+    expect_stdout: true
+}
+
+global_timeout_and_interval_symbols: {
+    options = {
+        pure_getters: "strict",
+        side_effects: true,
+        unsafe: true,
+    }
+    input: {
+        // These global symbols do not exist in the test sandbox
+        // and must be tested separately.
+        clearInterval;
+        clearTimeout;
+        setInterval;
+        setTimeout;
+    }
+    expect: {}
+}
+
+issue_2233_2: {
+    options = {
+        pure_getters: "strict",
+        reduce_vars: true,
+        side_effects: true,
+        unsafe: true,
+        unused: true,
+    }
+    input: {
+        var RegExp;
+        Array.isArray;
+        RegExp;
+        UndeclaredGlobal;
+        function foo() {
+            var Number;
+            AnotherUndeclaredGlobal;
+            Math.sin;
+            Number.isNaN;
+        }
+    }
+    expect: {
+        var RegExp;
+        UndeclaredGlobal;
+        function foo() {
+            var Number;
+            AnotherUndeclaredGlobal;
+            Number.isNaN;
+        }
+    }
+}
+
+issue_2233_3: {
+    options = {
+        pure_getters: "strict",
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+        unsafe: true,
+        unused: true,
+    }
+    input: {
+        var RegExp;
+        Array.isArray;
+        RegExp;
+        UndeclaredGlobal;
+        function foo() {
+            var Number;
+            AnotherUndeclaredGlobal;
+            Math.sin;
+            Number.isNaN;
+        }
+    }
+    expect: {
+        UndeclaredGlobal;
+    }
+}
+
+global_fns: {
+    options = {
+        side_effects: true,
+        unsafe: true,
+    }
+    input: {
+        Boolean(1, 2);
+        decodeURI(1, 2);
+        decodeURIComponent(1, 2);
+        Date(1, 2);
+        encodeURI(1, 2);
+        encodeURIComponent(1, 2);
+        Error(1, 2);
+        escape(1, 2);
+        EvalError(1, 2);
+        isFinite(1, 2);
+        isNaN(1, 2);
+        Number(1, 2);
+        Object(1, 2);
+        parseFloat(1, 2);
+        parseInt(1, 2);
+        RangeError(1, 2);
+        ReferenceError(1, 2);
+        String(1, 2);
+        SyntaxError(1, 2);
+        TypeError(1, 2);
+        unescape(1, 2);
+        URIError(1, 2);
+        try {
+            Function(1, 2);
+        } catch (e) {
+            console.log(e.name);
+        }
+        try {
+            RegExp(1, 2);
+        } catch (e) {
+            console.log(e.name);
+        }
+        try {
+            Array(NaN);
+        } catch (e) {
+            console.log(e.name);
+        }
+    }
+    expect: {
+        try {
+            Function(1, 2);
+        } catch (e) {
+            console.log(e.name);
+        }
+        try {
+            RegExp(1, 2);
+        } catch (e) {
+            console.log(e.name);
+        }
+        try {
+            Array(NaN);
+        } catch (e) {
+            console.log(e.name);
+        }
+    }
+    expect_stdout: [
+        "SyntaxError",
+        "SyntaxError",
+        "RangeError",
+    ]
+}

test/compress/destructuring.js

@@ -65,10 +65,10 @@ nested_destructuring_objects: {
     }
     input: {
         const [{a},b] = c;
-        let [{a},b] = c;
-        var [{a},b] = c;
+        let [{d},e] = f;
+        var [{g},h] = i;
     }
-    expect_exact: 'const[{a},b]=c;let[{a},b]=c;var[{a},b]=c;';
+    expect_exact: 'const[{a},b]=c;let[{d},e]=f;var[{g},h]=i;';
 }
 
 destructuring_constdef_in_loops: {
@@ -274,8 +274,8 @@ reduce_vars: {
         var {aa, bb: {cc, dd}} = {aa:1, bb: {cc:2, dd: 3}};
         ({aa, bb: {cc, dd}} = {aa:1, bb: {cc:2, dd: 3}});
         const [{a},b] = c;
-        let [{a},b] = c;
-        var [{a},b] = c;
+        let [{d},e] = f;
+        var [{g},h] = i;
         [{a},b] = c;
         for (const [x,y] in pairs);
         for (let [x,y] in pairs);
@@ -292,8 +292,8 @@ reduce_vars: {
         var {aa, bb: {cc, dd}} = {aa:1, bb: {cc:2, dd: 3}};
         ({aa, bb: {cc, dd}} = {aa:1, bb: {cc:2, dd: 3}});
         const [{a},b] = c;
-        let [{a},b] = c;
-        var [{a},b] = c;
+        let [{d},e] = f;
+        var [{g},h] = i;
         [{a},b] = c;
         for (const [x,y] in pairs);
         for (let [x,y] in pairs);

test/compress/drop-unused.js

@@ -1210,6 +1210,7 @@ var_catch_toplevel: {
             a--;
             try {
                 a++;
+                x();
             } catch(a) {
                 if (a) var a;
                 var a = 10;
@@ -1219,9 +1220,8 @@ var_catch_toplevel: {
     }
     expect: {
         !function() {
-            a--;
             try {
-                a++;
+                x();
             } catch(a) {
                 var a;
             }
@@ -1427,3 +1427,111 @@ issue_2163: {
         b;
     }
 }
+
+issue_2226_1: {
+    options = {
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        function f1() {
+            var a = b;
+            a += c;
+        }
+        function f2(a) {
+            a <<= b;
+        }
+        function f3(a) {
+            --a;
+        }
+        function f4() {
+            var a = b;
+            return a *= c;
+        }
+        function f5(a) {
+            x(a /= b);
+        }
+    }
+    expect: {
+        function f1() {
+            b;
+            c;
+        }
+        function f2(a) {
+            b;
+        }
+        function f3(a) {
+            0;
+        }
+        function f4() {
+            var a = b;
+            return a *= c;
+        }
+        function f5(a) {
+            x(a /= b);
+        }
+    }
+}
+
+issue_2226_2: {
+    options = {
+        cascade: true,
+        sequences: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        console.log(function(a, b) {
+            a += b;
+            return a;
+        }(1, 2));
+    }
+    expect: {
+        console.log(function(a, b) {
+            return a += b;
+        }(1, 2));
+    }
+    expect_stdout: "3"
+}
+
+issue_2226_3: {
+    options = {
+        collapse_vars: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        console.log(function(a, b) {
+            a += b;
+            return a;
+        }(1, 2));
+    }
+    expect: {
+        console.log(function(a, b) {
+            return a += 2;
+        }(1));
+    }
+    expect_stdout: "3"
+}
+
+issue_2288: {
+    options = {
+        unused: true,
+    }
+    beautify = {
+        beautify: true,
+    }
+    input: {
+        function foo(o) {
+            for (var j = o.a, i = 0; i < 0; i++);
+            for (var i = 0; i < 0; i++);
+        }
+    }
+    expect: {
+        function foo(o) {
+            o.a;
+            for (i = 0; i < 0; i++);
+            for (var i = 0; i < 0; i++);
+        }
+    }
+}

test/compress/evaluate.js

@@ -1250,3 +1250,31 @@ issue_2207_3: {
     }
     expect_stdout: true
 }
+
+issue_2231_1: {
+    options = {
+        evaluate: true,
+        unsafe: true,
+    }
+    input: {
+        console.log(Object.keys(void 0));
+    }
+    expect: {
+        console.log(Object.keys(void 0));
+    }
+    expect_stdout: true
+}
+
+issue_2231_2: {
+    options = {
+        evaluate: true,
+        unsafe: true,
+    }
+    input: {
+        console.log(Object.getOwnPropertyNames(null));
+    }
+    expect: {
+        console.log(Object.getOwnPropertyNames(null));
+    }
+    expect_stdout: true
+}

test/compress/expansions.js

@@ -26,3 +26,46 @@ expand_parameters: {
     expect_exact: "(function(a,...b){});(function(...args){});"
 }
 
+avoid_spread_in_ternary: {
+    options = {
+        comparisons: true,
+        conditionals: true,
+        evaluate: true,
+    }
+    input: {
+        function print(...x) {
+            console.log(...x);
+        }
+        var a = [1, 2], b = [3, 4];
+
+        if (Math)
+            print(a);
+        else
+            print(b);
+
+        if (Math)
+            print(...a);
+        else
+            print(b);
+
+        if (Math.no_such_property)
+            print(a);
+        else
+            print(...b);
+    }
+    expect: {
+        function print(...x) {
+            console.log(...x);
+        }
+        var a = [ 1, 2 ], b = [ 3, 4 ];
+        print(Math ? a : b);
+        Math ? print(...a) : print(b);
+        Math.no_such_property ? print(a) : print(...b);
+    }
+    expect_stdout: [
+        "[ 1, 2 ]",
+        "1 2",
+        "3 4",
+    ]
+    node_version: ">=6"
+}

test/compress/harmony.js

@@ -211,13 +211,13 @@ export_statement: {
     }
     input: {
         export default 1 + 2;
-        export var foo = 4;
-        export let foo = 6;
-        export const foo = 6;
-        export function foo() {};
-        export class foo { };
+        export var a = 4;
+        export let b = 6;
+        export const c = 6;
+        export function d() {};
+        export class e {};
     }
-    expect_exact: "export default 3;export var foo=4;export let foo=6;export const foo=6;export function foo(){};export class foo{};"
+    expect_exact: "export default 3;export var a=4;export let b=6;export const c=6;export function d(){};export class e{};"
 }
 
 export_default_object_expression: {
@@ -695,3 +695,112 @@ export_default_class_decl: {
     }
     expect_exact: "export default class Car{};export class Cab{};"
 }
+
+object_rest_spread: {
+    mangle = {
+        toplevel: true,
+    }
+    input: {
+        var   { w: w1, ...V } = { w: 7, x: 1, y: 2 }; console.log(w1, V);
+        let   { w: w2, ...L } = { w: 8, x: 3, y: 4 }; console.log(w2, L);
+        const { w: w3, ...C } = { w: 9, x: 5, y: 6 }; console.log(w3, C);
+
+        let b;
+        ({ b, ...V } = { a: 1, b: 2, c: 3 }); console.log(V);
+        ({ b, ...L } = { a: 4, b: 5, c: 6 }); console.log(L);
+
+        (function({ y, ...p }){ console.log(p); })({ x: 1, y: 2, z: 3 });
+        (({ y, ...p }) =>     { console.log(p); })({ x: 4, y: 5, z: 6 });
+
+        const T = { a: 1, b: 2 }; console.log({ ...T, w: 0, ...{}, ...L, ...{K: 9} });
+    }
+    expect: {
+        var   { w: o, ...l } = { w: 7, x: 1, y: 2 }; console.log(o, l);
+        let   { w: c, ...n } = { w: 8, x: 3, y: 4 }; console.log(c, n);
+        const { w: e, ...s } = { w: 9, x: 5, y: 6 }; console.log(e, s);
+
+        let g;
+        ({ b: g, ...l } = { a: 1, b: 2, c: 3 }); console.log(l);
+        ({ b: g, ...n } = { a: 4, b: 5, c: 6 }); console.log(n);
+
+        (function({ y: o, ...l }) { console.log(l); })({ x: 1, y: 2, z: 3 });
+        (({ y: o, ...l }) =>      { console.log(l); })({ x: 4, y: 5, z: 6 });
+
+        const w = { a: 1, b: 2 }; console.log({ ...w, w: 0, ...{}, ...n, ...{ K: 9 } });
+    }
+}
+
+object_spread_unsafe: {
+    options = {
+        collapse_vars: true,
+        evaluate: true,
+        join_vars: true,
+        passes: 3,
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+        unsafe: true,
+        unused: true,
+    }
+    mangle = {
+        toplevel: true,
+    }
+    input: {
+        var o1 = { x: 1, y: 2 };
+        var o2 = { x: 3, z: 4 };
+        var cloned = { ...o1 };
+        var merged = { ...o1, ...o2 };
+        console.log(cloned, merged);
+    }
+    expect: {
+        var o = { x: 1, y: 2 }, l = { ...o }, x = { ...o, ...{ x: 3, z: 4 } };
+        console.log(l, x);
+    }
+}
+
+array_spread_of_sequence: {
+    mangle = {
+        toplevel: true,
+    }
+    input: {
+        var a = [1];
+        console.log([...(a, a)]);
+        console.log([...a, a]);
+        console.log([...(a || a)]);
+        console.log([...a || a]);
+    }
+    expect: {
+        var o = [1];
+        console.log([...(o, o)]);
+        console.log([...o, o]);
+        console.log([...o || o]);
+        console.log([...o || o]);
+    }
+    expect_stdout: [
+        "[ 1 ]",
+        "[ 1, [ 1 ] ]",
+        "[ 1 ]",
+        "[ 1 ]",
+    ]
+    node_version: ">=6"
+}
+
+object_spread_of_sequence: {
+    mangle = {
+        toplevel: true,
+    }
+    input: {
+        var a = {x: 1};
+        console.log({ ...(a, a) });
+        console.log({ ...a, a });
+        console.log({ ...(a || a) });
+        console.log({ ...a || a });
+    }
+    expect: {
+        var o = { x: 1 };
+        console.log({ ...(o, o) });
+        console.log({ ...o, a: o });
+        console.log({ ...o || o });
+        console.log({ ...o || o });
+    }
+}

test/compress/hoist_vars.js

@@ -88,3 +88,24 @@ sequences_funs: {
         }
     }
 }
+
+issue_2295: {
+    options = {
+        collapse_vars: true,
+        hoist_vars: true,
+    }
+    input: {
+        function foo(o) {
+            var a = o.a;
+            if (a) return a;
+            var a = 1;
+        }
+    }
+    expect: {
+        function foo(o) {
+            var a = o.a;
+            if (a) return a;
+            a = 1;
+        }
+    }
+}

test/compress/issue-1034.js

@@ -71,11 +71,13 @@ non_hoisted_function_after_return_2a: {
         "WARN: Declarations in unreachable code! [test/compress/issue-1034.js:51,16]",
         "WARN: Dropping unused variable a [test/compress/issue-1034.js:48,20]",
         "WARN: Dropping unused function nope [test/compress/issue-1034.js:55,21]",
+        "WARN: pass 0: last_count: Infinity, count: 37",
         "WARN: Dropping unreachable code [test/compress/issue-1034.js:53,12]",
         "WARN: Declarations in unreachable code! [test/compress/issue-1034.js:53,12]",
         "WARN: Dropping unreachable code [test/compress/issue-1034.js:56,12]",
         "WARN: Dropping unused variable b [test/compress/issue-1034.js:51,20]",
         "WARN: Dropping unused variable c [test/compress/issue-1034.js:53,16]",
+        "WARN: pass 1: last_count: 37, count: 18",
     ]
 }
 
@@ -109,11 +111,11 @@ non_hoisted_function_after_return_2b: {
     }
     expect_warnings: [
         // duplicate warnings no longer emitted
-        "WARN: Dropping unreachable code [test/compress/issue-1034.js:95,16]",
-        "WARN: Declarations in unreachable code! [test/compress/issue-1034.js:95,16]",
-        "WARN: Dropping unreachable code [test/compress/issue-1034.js:97,12]",
-        "WARN: Declarations in unreachable code! [test/compress/issue-1034.js:97,12]",
-        "WARN: Dropping unreachable code [test/compress/issue-1034.js:101,12]",
+        "WARN: Dropping unreachable code [test/compress/issue-1034.js:97,16]",
+        "WARN: Declarations in unreachable code! [test/compress/issue-1034.js:97,16]",
+        "WARN: Dropping unreachable code [test/compress/issue-1034.js:99,12]",
+        "WARN: Declarations in unreachable code! [test/compress/issue-1034.js:99,12]",
+        "WARN: Dropping unreachable code [test/compress/issue-1034.js:103,12]",
     ]
 }
 
@@ -151,10 +153,10 @@ non_hoisted_function_after_return_strict: {
     }
     expect_stdout: "8 7"
     expect_warnings: [
-        'WARN: Dropping unreachable code [test/compress/issue-1034.js:131,16]',
-        "WARN: Dropping unreachable code [test/compress/issue-1034.js:134,16]",
-        "WARN: Dropping unreachable code [test/compress/issue-1034.js:137,12]",
-        "WARN: Dropping unused function UnusedFunction [test/compress/issue-1034.js:138,21]"
+        "WARN: Dropping unreachable code [test/compress/issue-1034.js:133,16]",
+        "WARN: Dropping unreachable code [test/compress/issue-1034.js:136,16]",
+        "WARN: Dropping unreachable code [test/compress/issue-1034.js:139,12]",
+        "WARN: Dropping unused function UnusedFunction [test/compress/issue-1034.js:140,21]",
     ]
 }
 
@@ -194,17 +196,19 @@ non_hoisted_function_after_return_2a_strict: {
     }
     expect_stdout: "5 6"
     expect_warnings: [
-        "WARN: Dropping unreachable code [test/compress/issue-1034.js:173,16]",
-        "WARN: Declarations in unreachable code! [test/compress/issue-1034.js:173,16]",
-        "WARN: Dropping unreachable code [test/compress/issue-1034.js:176,16]",
-        "WARN: Declarations in unreachable code! [test/compress/issue-1034.js:176,16]",
-        "WARN: Dropping unused variable a [test/compress/issue-1034.js:173,20]",
-        "WARN: Dropping unused function nope [test/compress/issue-1034.js:180,21]",
-        "WARN: Dropping unreachable code [test/compress/issue-1034.js:178,12]",
-        "WARN: Declarations in unreachable code! [test/compress/issue-1034.js:178,12]",
-        "WARN: Dropping unreachable code [test/compress/issue-1034.js:181,12]",
-        "WARN: Dropping unused variable b [test/compress/issue-1034.js:176,20]",
-        "WARN: Dropping unused variable c [test/compress/issue-1034.js:178,16]",
+        "WARN: Dropping unreachable code [test/compress/issue-1034.js:175,16]",
+        "WARN: Declarations in unreachable code! [test/compress/issue-1034.js:175,16]",
+        "WARN: Dropping unreachable code [test/compress/issue-1034.js:178,16]",
+        "WARN: Declarations in unreachable code! [test/compress/issue-1034.js:178,16]",
+        "WARN: Dropping unused variable a [test/compress/issue-1034.js:175,20]",
+        "WARN: Dropping unused function nope [test/compress/issue-1034.js:182,21]",
+        "WARN: pass 0: last_count: Infinity, count: 48",
+        "WARN: Dropping unreachable code [test/compress/issue-1034.js:180,12]",
+        "WARN: Declarations in unreachable code! [test/compress/issue-1034.js:180,12]",
+        "WARN: Dropping unreachable code [test/compress/issue-1034.js:183,12]",
+        "WARN: Dropping unused variable b [test/compress/issue-1034.js:178,20]",
+        "WARN: Dropping unused variable c [test/compress/issue-1034.js:180,16]",
+        "WARN: pass 1: last_count: 48, count: 29",
     ]
 }
 
@@ -243,10 +247,10 @@ non_hoisted_function_after_return_2b_strict: {
     expect_stdout: "5 6"
     expect_warnings: [
         // duplicate warnings no longer emitted
-        "WARN: Dropping unreachable code [test/compress/issue-1034.js:225,16]",
-        "WARN: Declarations in unreachable code! [test/compress/issue-1034.js:225,16]",
-        "WARN: Dropping unreachable code [test/compress/issue-1034.js:227,12]",
-        "WARN: Declarations in unreachable code! [test/compress/issue-1034.js:227,12]",
+        "WARN: Dropping unreachable code [test/compress/issue-1034.js:229,16]",
+        "WARN: Declarations in unreachable code! [test/compress/issue-1034.js:229,16]",
         "WARN: Dropping unreachable code [test/compress/issue-1034.js:231,12]",
+        "WARN: Declarations in unreachable code! [test/compress/issue-1034.js:231,12]",
+        "WARN: Dropping unreachable code [test/compress/issue-1034.js:235,12]",
     ]
 }

test/compress/issue-1261.js

@@ -96,6 +96,13 @@ pure_function_calls_toplevel: {
             })();
         })();
 
+        // pure top-level calls will be dropped regardless of the leading comments position
+        var MyClass = /*#__PURE__*//*@class*/(function(){
+            function MyClass() {}
+            MyClass.prototype.method = function() {};
+            return MyClass;
+        })();
+
         // comment #__PURE__ comment
         bar(), baz(), quux();
         a.b(), /* @__PURE__ */ c.d.e(), f.g();
@@ -110,10 +117,12 @@ pure_function_calls_toplevel: {
         "WARN: Dropping __PURE__ call [test/compress/issue-1261.js:92,37]",
         "WARN: Dropping unused variable iife2 [test/compress/issue-1261.js:92,16]",
         "WARN: Dropping side-effect-free statement [test/compress/issue-1261.js:90,8]",
-        "WARN: Dropping __PURE__ call [test/compress/issue-1261.js:100,8]",
-        "WARN: Dropping __PURE__ call [test/compress/issue-1261.js:101,31]",
+        "WARN: Dropping __PURE__ call [test/compress/issue-1261.js:107,8]",
+        "WARN: Dropping __PURE__ call [test/compress/issue-1261.js:108,31]",
         "WARN: Dropping __PURE__ call [test/compress/issue-1261.js:84,33]",
         "WARN: Dropping unused variable iife1 [test/compress/issue-1261.js:84,12]",
+        "WARN: Dropping __PURE__ call [test/compress/issue-1261.js:100,45]",
+        "WARN: Dropping unused variable MyClass [test/compress/issue-1261.js:100,12]",
     ]
 }
 
@@ -148,29 +157,29 @@ should_warn: {
         baz();
     }
     expect_warnings: [
-        "WARN: Dropping __PURE__ call [test/compress/issue-1261.js:128,61]",
-        "WARN: Dropping __PURE__ call [test/compress/issue-1261.js:128,23]",
-        "WARN: Dropping side-effect-free statement [test/compress/issue-1261.js:128,23]",
-        "WARN: Boolean || always true [test/compress/issue-1261.js:129,23]",
-        "WARN: Dropping __PURE__ call [test/compress/issue-1261.js:129,23]",
-        "WARN: Condition always true [test/compress/issue-1261.js:129,23]",
-        "WARN: Condition left of || always true [test/compress/issue-1261.js:130,8]",
-        "WARN: Condition always true [test/compress/issue-1261.js:130,8]",
-        "WARN: Boolean && always false [test/compress/issue-1261.js:131,23]",
-        "WARN: Dropping __PURE__ call [test/compress/issue-1261.js:131,23]",
-        "WARN: Condition always false [test/compress/issue-1261.js:131,23]",
-        "WARN: Condition left of && always false [test/compress/issue-1261.js:132,8]",
-        "WARN: Condition always false [test/compress/issue-1261.js:132,8]",
-        "WARN: + in boolean context always true [test/compress/issue-1261.js:133,23]",
-        "WARN: Dropping __PURE__ call [test/compress/issue-1261.js:133,23]",
-        "WARN: Condition always true [test/compress/issue-1261.js:133,23]",
-        "WARN: + in boolean context always true [test/compress/issue-1261.js:134,8]",
-        "WARN: Dropping __PURE__ call [test/compress/issue-1261.js:134,31]",
-        "WARN: Condition always true [test/compress/issue-1261.js:134,8]",
-        "WARN: Dropping __PURE__ call [test/compress/issue-1261.js:135,23]",
-        "WARN: Dropping __PURE__ call [test/compress/issue-1261.js:136,24]",
-        "WARN: Condition always true [test/compress/issue-1261.js:136,8]",
-        "WARN: Dropping __PURE__ call [test/compress/issue-1261.js:137,31]",
-        "WARN: Condition always false [test/compress/issue-1261.js:137,8]",
+        "WARN: Dropping __PURE__ call [test/compress/issue-1261.js:137,61]",
+        "WARN: Dropping __PURE__ call [test/compress/issue-1261.js:137,23]",
+        "WARN: Dropping side-effect-free statement [test/compress/issue-1261.js:137,23]",
+        "WARN: Boolean || always true [test/compress/issue-1261.js:138,23]",
+        "WARN: Dropping __PURE__ call [test/compress/issue-1261.js:138,23]",
+        "WARN: Condition always true [test/compress/issue-1261.js:138,23]",
+        "WARN: Condition left of || always true [test/compress/issue-1261.js:139,8]",
+        "WARN: Condition always true [test/compress/issue-1261.js:139,8]",
+        "WARN: Boolean && always false [test/compress/issue-1261.js:140,23]",
+        "WARN: Dropping __PURE__ call [test/compress/issue-1261.js:140,23]",
+        "WARN: Condition always false [test/compress/issue-1261.js:140,23]",
+        "WARN: Condition left of && always false [test/compress/issue-1261.js:141,8]",
+        "WARN: Condition always false [test/compress/issue-1261.js:141,8]",
+        "WARN: + in boolean context always true [test/compress/issue-1261.js:142,23]",
+        "WARN: Dropping __PURE__ call [test/compress/issue-1261.js:142,23]",
+        "WARN: Condition always true [test/compress/issue-1261.js:142,23]",
+        "WARN: + in boolean context always true [test/compress/issue-1261.js:143,8]",
+        "WARN: Dropping __PURE__ call [test/compress/issue-1261.js:143,31]",
+        "WARN: Condition always true [test/compress/issue-1261.js:143,8]",
+        "WARN: Dropping __PURE__ call [test/compress/issue-1261.js:144,23]",
+        "WARN: Dropping __PURE__ call [test/compress/issue-1261.js:145,24]",
+        "WARN: Condition always true [test/compress/issue-1261.js:145,8]",
+        "WARN: Dropping __PURE__ call [test/compress/issue-1261.js:146,31]",
+        "WARN: Condition always false [test/compress/issue-1261.js:146,8]",
     ]
 }

test/compress/issue-1321.js

@@ -1,6 +1,8 @@
 issue_1321_no_debug: {
-    mangle_props = {
-        keep_quoted: true
+    mangle = {
+        properties: {
+            keep_quoted: true,
+        },
     }
     input: {
         var x = {};
@@ -10,17 +12,19 @@ issue_1321_no_debug: {
     }
     expect: {
         var x = {};
-        x.o = 1;
-        x["a"] = 2 * x.o;
-        console.log(x.o, x["a"]);
+        x.x = 1;
+        x["a"] = 2 * x.x;
+        console.log(x.x, x["a"]);
     }
     expect_stdout: true
 }
 
 issue_1321_debug: {
-    mangle_props = {
-        keep_quoted: true,
-        debug: ""
+    mangle = {
+        properties: {
+            debug: "",
+            keep_quoted: true,
+        },
     }
     input: {
         var x = {};
@@ -30,16 +34,18 @@ issue_1321_debug: {
     }
     expect: {
         var x = {};
-        x.o = 1;
-        x["_$foo$_"] = 2 * x.o;
-        console.log(x.o, x["_$foo$_"]);
+        x.x = 1;
+        x["_$foo$_"] = 2 * x.x;
+        console.log(x.x, x["_$foo$_"]);
     }
     expect_stdout: true
 }
 
 issue_1321_with_quoted: {
-    mangle_props = {
-        keep_quoted: false
+    mangle = {
+        properties: {
+            keep_quoted: false,
+        },
     }
     input: {
         var x = {};
@@ -49,9 +55,9 @@ issue_1321_with_quoted: {
     }
     expect: {
         var x = {};
-        x.o = 1;
-        x["x"] = 2 * x.o;
-        console.log(x.o, x["x"]);
+        x.x = 1;
+        x["o"] = 2 * x.x;
+        console.log(x.x, x["o"]);
     }
     expect_stdout: true
 }

test/compress/issue-1770.js

@@ -1,5 +1,7 @@
 mangle_props: {
-    mangle_props = {}
+    mangle = {
+        properties: true,
+    }
     input: {
         var obj = {
             undefined: 1,
@@ -54,10 +56,12 @@ mangle_props: {
 }
 
 numeric_literal: {
+    mangle = {
+        properties: true,
+    }
     beautify = {
         beautify: true,
     }
-    mangle_props = {}
     input: {
         var obj = {
             0: 0,

test/compress/issue-203.js

@@ -36,9 +36,10 @@ compress_new_function_with_destruct: {
 compress_new_function_with_destruct_arrows: {
     options = {
         arrows: true,
+        unsafe_arrows: true,
         unsafe: true,
         unsafe_Func: true,
-        ecma: 6
+        ecma: 6,
     }
     beautify = {
         ecma: 6

test/compress/issue-747.js

@@ -1,6 +1,8 @@
 dont_reuse_prop: {
-    mangle_props = {
-        regex: /asd/
+    mangle = {
+        properties: {
+            regex: /asd/,
+        },
     }
     input: {
         "aaaaaaaaaabbbbb";
@@ -20,8 +22,10 @@ dont_reuse_prop: {
 }
 
 unmangleable_props_should_always_be_reserved: {
-    mangle_props = {
-        regex: /asd/
+    mangle = {
+        properties: {
+            regex: /asd/,
+        },
     }
     input: {
         "aaaaaaaaaabbbbb";

test/compress/object.js

@@ -284,9 +284,11 @@ concise_methods_with_various_property_names: {
 }
 
 concise_methods_and_mangle_props: {
-    mangle_props = {
-        regex: /_/
-    };
+    mangle = {
+        properties: {
+            regex: /_/,
+        },
+    }
     input: {
         function x() {
             obj = {

test/compress/parameters.js

@@ -142,11 +142,11 @@ destructuring_arguments_3: {
     }
     input: {
         function fn3({x: {y: {z: {} = 42}}}) {}
-        const { cover = (function () {}), xCover = (0, function() {})  } = {};
-        let { cover = (function () {}), xCover = (0, function() {})  } = {};
-        var { cover = (function () {}), xCover = (0, function() {})  } = {};
+        const { a = (function () {}), b = (0, function() {})  } = {};
+        let { c = (function () {}), d = (0, function() {})  } = {};
+        var { e = (function () {}), f = (0, function() {})  } = {};
     }
-    expect_exact: "function fn3({x:{y:{z:{}=42}}}){}const{cover=function(){},xCover=(0,function(){})}={};let{cover=function(){},xCover=(0,function(){})}={};var{cover=function(){},xCover=(0,function(){})}={};"
+    expect_exact: "function fn3({x:{y:{z:{}=42}}}){}const{a=function(){},b=(0,function(){})}={};let{c=function(){},d=(0,function(){})}={};var{e=function(){},f=(0,function(){})}={};"
 }
 
 default_arguments: {

test/compress/properties.js

@@ -13,8 +13,10 @@ keep_properties: {
 dot_properties: {
     options = {
         properties: true,
+    }
+    beautify = {
         ie8: true,
-    };
+    }
     input: {
         a["foo"] = "bar";
         a["if"] = "if";
@@ -36,8 +38,10 @@ dot_properties: {
 dot_properties_es5: {
     options = {
         properties: true,
+    }
+    beautify = {
         ie8: false,
-    };
+    }
     input: {
         a["foo"] = "bar";
         a["if"] = "if";
@@ -124,9 +128,11 @@ evaluate_string_length: {
 }
 
 mangle_properties: {
-    mangle_props = {
-        keep_quoted: false
-    };
+    mangle = {
+        properties: {
+            keep_quoted: false,
+        },
+    }
     input: {
         a["foo"] = "bar";
         a.color = "red";
@@ -135,11 +141,11 @@ mangle_properties: {
         a['run']({color: "blue", foo: "baz"});
     }
     expect: {
-        a["o"] = "bar";
-        a.a = "red";
-        x = {r: 10};
-        a.b(x.r, a.o);
-        a['b']({a: "blue", o: "baz"});
+        a["a"] = "bar";
+        a.b = "red";
+        x = {o: 10};
+        a.r(x.o, a.a);
+        a['r']({b: "blue", a: "baz"});
     }
 }
 
@@ -147,9 +153,11 @@ mangle_unquoted_properties: {
     options = {
         properties: false
     }
-    mangle_props = {
-        builtins: true,
-        keep_quoted: true
+    mangle = {
+        properties: {
+            builtins: true,
+            keep_quoted: true,
+        },
     }
     beautify = {
         beautify: false,
@@ -178,24 +186,26 @@ mangle_unquoted_properties: {
         function f1() {
             a["foo"] = "bar";
             a.color = "red";
-            a.o = 2;
-            x = {"bar": 10, f: 7};
-            a.f = 9;
+            a.r = 2;
+            x = {"bar": 10, b: 7};
+            a.b = 9;
         }
         function f2() {
             a.foo = "bar";
             a['color'] = "red";
-            x = {bar: 10, f: 7};
-            a.f = 9;
-            a.o = 3;
+            x = {bar: 10, b: 7};
+            a.b = 9;
+            a.r = 3;
         }
     }
 }
 
 mangle_debug: {
-    mangle_props = {
-        debug: ""
-    };
+    mangle = {
+        properties: {
+            debug: "",
+        },
+    }
     input: {
         a.foo = "bar";
         x = { baz: "ban" };
@@ -207,9 +217,11 @@ mangle_debug: {
 }
 
 mangle_debug_true: {
-    mangle_props = {
-        debug: true
-    };
+    mangle = {
+        properties: {
+            debug: true,
+        },
+    }
     input: {
         a.foo = "bar";
         x = { baz: "ban" };
@@ -221,9 +233,11 @@ mangle_debug_true: {
 }
 
 mangle_debug_suffix: {
-    mangle_props = {
-        debug: "XYZ"
-    };
+    mangle = {
+        properties: {
+            debug: "XYZ",
+        },
+    }
     input: {
         a.foo = "bar";
         x = { baz: "ban" };
@@ -238,11 +252,13 @@ mangle_debug_suffix_keep_quoted: {
     options = {
         properties: false
     }
-    mangle_props = {
-        builtins: true,
-        keep_quoted: true,
-        debug: "XYZ",
-        reserved: []
+    mangle = {
+        properties: {
+            builtins: true,
+            debug: "XYZ",
+            keep_quoted: true,
+            reserved: [],
+        },
     }
     beautify = {
         beautify: false,
@@ -866,3 +882,85 @@ issue_2208_9: {
     expect_stdout: "42"
     node_version: ">=4"
 }
+
+methods_keep_quoted_true: {
+    options = {
+        arrows: true,
+        ecma: 6,
+    }
+    mangle = {
+        properties: {
+            keep_quoted: true,
+        },
+    }
+    input: {
+        class C { "Quoted"(){} Unquoted(){} }
+        f1({ "Quoted"(){}, Unquoted(){}, "Prop": 3 });
+        f2({ "Quoted": function(){} });
+        f3({ "Quoted": ()=>{} });
+    }
+    expect_exact: "class C{Quoted(){}o(){}}f1({Quoted(){},o(){},Prop:3});f2({Quoted(){}});f3({Quoted(){}});"
+}
+
+methods_keep_quoted_false: {
+    options = {
+        arrows: true,
+        ecma: 6,
+    }
+    mangle = {
+        properties: {
+            keep_quoted: false,
+        },
+    }
+    input: {
+        class C { "Quoted"(){} Unquoted(){} }
+        f1({ "Quoted"(){}, Unquoted(){}, "Prop": 3 });
+        f2({ "Quoted": function(){} });
+        f3({ "Quoted": ()=>{} });
+    }
+    expect_exact: "class C{o(){}d(){}}f1({o(){},d(){},e:3});f2({o(){}});f3({o(){}});"
+}
+
+methods_keep_quoted_from_dead_code: {
+    options = {
+        arrows: true,
+        booleans: true,
+        conditionals: true,
+        dead_code: true,
+        ecma: 6,
+        evaluate: true,
+        reduce_vars: true,
+        side_effects: true,
+    }
+    mangle = {
+        properties: {
+            keep_quoted: true,
+        },
+    }
+    input: {
+        class C { Quoted(){} Unquoted(){} }
+        f1({ Quoted(){}, Unquoted(){}, "Prop": 3 });
+        f2({ Quoted: function(){} });
+        f3({ Quoted: ()=>{} });
+        0 && obj["Quoted"];
+    }
+    expect_exact: "class C{Quoted(){}o(){}}f1({Quoted(){},o(){},Prop:3});f2({Quoted(){}});f3({Quoted(){}});"
+}
+
+issue_2256: {
+    options = {
+        side_effects: true,
+    }
+    mangle = {
+        properties: {
+            keep_quoted: true,
+        },
+    }
+    input: {
+        ({ "keep": 1 });
+        g.keep = g.change;
+    }
+    expect: {
+        g.keep = g.g;
+    }
+}

test/compress/pure_getters.js

@@ -385,3 +385,76 @@ set_mutable_2: {
     }
     expect_stdout: "PASS"
 }
+
+issue_2265_1: {
+    options = {
+        pure_getters: "strict",
+        side_effects: true,
+    }
+    input: {
+        ({ ...{} }).p;
+        ({ ...g }).p;
+    }
+    expect: {
+        ({ ...g }).p;
+    }
+}
+
+issue_2265_2: {
+    options = {
+        pure_getters: "strict",
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+    }
+    input: {
+        var a = {
+            get b() {
+                throw 0;
+            }
+        };
+        ({...a}).b;
+    }
+    expect: {
+        var a = {
+            get b() {
+                throw 0;
+            }
+        };
+        ({...a}).b;
+    }
+}
+
+issue_2265_3: {
+    options = {
+        pure_getters: "strict",
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = {
+            set b() {
+                throw 0;
+            }
+        };
+        ({...a}).b;
+    }
+    expect: {}
+}
+
+issue_2265_4: {
+    options = {
+        pure_getters: "strict",
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = { b: 1 };
+        ({...a}).b;
+    }
+    expect: {}
+}

test/compress/screw-ie8.js

@@ -325,3 +325,69 @@ issue_2120_2: {
     }
     expect_stdout: "PASS"
 }
+
+issue_2254_1: {
+    mangle = {
+        ie8: false,
+    }
+    input: {
+        "eeeeee";
+        try {
+            console.log(f("PASS"));
+        } catch (e) {}
+        function f(s) {
+            try {
+                throw "FAIL";
+            } catch (e) {
+                return s;
+            }
+        }
+    }
+    expect: {
+        "eeeeee";
+        try {
+            console.log(f("PASS"));
+        } catch (e) {}
+        function f(e) {
+            try {
+                throw "FAIL";
+            } catch (t) {
+                return e;
+            }
+        }
+    }
+    expect_stdout: "PASS"
+}
+
+issue_2254_2: {
+    mangle = {
+        ie8: true,
+    }
+    input: {
+        "eeeeee";
+        try {
+            console.log(f("PASS"));
+        } catch (e) {}
+        function f(s) {
+            try {
+                throw "FAIL";
+            } catch (e) {
+                return s;
+            }
+        }
+    }
+    expect: {
+        "eeeeee";
+        try {
+            console.log(f("PASS"));
+        } catch (e) {}
+        function f(t) {
+            try {
+                throw "FAIL";
+            } catch (e) {
+                return t;
+            }
+        }
+    }
+    expect_stdout: "PASS"
+}

test/compress/unicode.js

@@ -43,15 +43,6 @@ unicode_string_literals: {
     expect_exact: 'var a="6 length unicode character: \\u{101111}";'
 }
 
-// Don't escape identifiers below es6 (or in this case double escaped in expect_exact)
-unicode_output_es5_surrogates: {
-    beautify = {ascii_only: true, ecma: 5}
-    input: {
-        var \u{10000} = "6 length unicode character: \u{10FFFF}";
-    }
-    expect_exact: 'var \u{10000}="6 length unicode character: \\udbff\\udfff";'
-}
-
 check_escape_style: {
     beautify = {ascii_only: true, ecma: 6}
     input: {
@@ -65,20 +56,6 @@ check_escape_style: {
     expect_exact: 'var a="\\x01";var \\ua0081="\\x10";var \\u0100="\\u0100";var \\u1000="\\u1000";var \\u{10000}="\\u{10000}";var \\u{2f800}="\\u{100000}";'
 }
 
-// Don't escape identifiers below es6, no escaped identifiers support and no \u{} syntax
-check_escape_style_es5: {
-    beautify = {ascii_only: true, ecma: 5}
-    input: {
-        var a = "\x01";
-        var \ua0081 = "\x10"; // \u0081 only in ID_Continue
-        var \u0100 = "\u0100";
-        var \u1000 = "\u1000";
-        var \u{10000} = "\u{10000}"; // Identifier won't be escaped in es 5.1
-        var \u{2f800} = "\u{100000}"; // Same
-    }
-    expect_exact: 'var a="\\x01";var \\ua0081="\\x10";var \\u0100="\\u0100";var \\u1000="\\u1000";var \ud800\udc00="\\ud800\\udc00";var \ud87e\udc00="\\udbc0\\udc00";'
-}
-
 ID_continue_with_surrogate_pair: {
     beautify = {ascii_only: true, ecma: 6}
     input: {
@@ -103,18 +80,42 @@ non_escape_2_non_escape: {
     expect_exact: 'var µþ="µþ";'
 }
 
-non_escape_2_half_escape1: {
-    beautify = {ascii_only: false, ascii_identifiers: true, ecma: 6}
-    input: {
-        var µþ = "µþ";
+issue_2242_1: {
+    beautify = {
+        ascii_only: false,
     }
-    expect_exact: 'var \\u00b5\\u00fe="µþ";'
+    input: {
+        console.log("\ud83d", "\ude00", "\ud83d\ude00", "\ud83d@\ude00");
+    }
+    expect_exact: 'console.log("\\ud83d","\\ude00","\ud83d\ude00","\\ud83d@\\ude00");'
 }
 
-non_escape_2_half_escape2: {
-    beautify = {ascii_only: true, ascii_identifiers: false, ecma: 6}
-    input: {
-        var µþ = "µþ";
+issue_2242_2: {
+    beautify = {
+        ascii_only: true,
     }
-    expect_exact: 'var µþ="\\xb5\\xfe";'
-}
+    input: {
+        console.log("\ud83d", "\ude00", "\ud83d\ude00", "\ud83d@\ude00");
+    }
+    expect_exact: 'console.log("\\ud83d","\\ude00","\\ud83d\\ude00","\\ud83d@\\ude00");'
+}
+
+issue_2242_3: {
+    options = {
+        evaluate: false,
+    }
+    input: {
+        console.log("\ud83d" + "\ude00", "\ud83d" + "@" + "\ude00");
+    }
+    expect_exact: 'console.log("\\ud83d"+"\\ude00","\\ud83d"+"@"+"\\ude00");'
+}
+
+issue_2242_4: {
+    options = {
+        evaluate: true,
+    }
+    input: {
+        console.log("\ud83d" + "\ude00", "\ud83d" + "@" + "\ude00");
+    }
+    expect_exact: 'console.log("\ud83d\ude00","\\ud83d@\\ude00");'
+}

test/exports.js

@@ -8,6 +8,7 @@ exports["defaults"] = defaults;
 exports["mangle_properties"] = mangle_properties;
 exports["minify"] = minify;
 exports["parse"] = parse;
+exports["reserve_quoted_keys"] = reserve_quoted_keys;
 exports["string_template"] = string_template;
 exports["tokenizer"] = tokenizer;
 exports["is_identifier"] = is_identifier;

test/mocha/cli.js

@@ -66,7 +66,7 @@ describe("bin/uglifyjs", function () {
             if (err) throw err;
 
             assert.strictEqual(stdout, "var bar=function(){function foo(bar){return bar}return foo}();\n" +
-                "//# sourceMappingURL=data:application/json;charset=utf-8;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbInRlc3QvaW5wdXQvaXNzdWUtMTMyMy9zYW1wbGUuanMiXSwibmFtZXMiOlsiYmFyIiwiZm9vIl0sIm1hcHBpbmdzIjoiQUFBQSxJQUFJQSxJQUFNLFdBQ04sU0FBU0MsSUFBS0QsS0FDVixPQUFPQSxJQUdYLE9BQU9DIn0=\n");
+                "//# sourceMappingURL=data:application/json;charset=utf-8;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbInRlc3QvaW5wdXQvaXNzdWUtMTMyMy9zYW1wbGUuanMiXSwibmFtZXMiOlsiYmFyIiwiZm9vIl0sIm1hcHBpbmdzIjoiQUFBQSxJQUFJQSxJQUFNLFdBQ04sU0FBU0MsSUFBS0QsS0FDVixPQUFPQSxJQUdYLE9BQU9DLElBTEQifQ==\n");
             done();
         });
     });
@@ -195,7 +195,7 @@ describe("bin/uglifyjs", function () {
 
             assert.strictEqual(stdout, [
                 "var bar=function(){function foo(bar){return bar}return foo}();",
-                "//# sourceMappingURL=data:application/json;charset=utf-8;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbInRlc3QvaW5wdXQvaXNzdWUtMTMyMy9zYW1wbGUuanMiXSwibmFtZXMiOlsiYmFyIiwiZm9vIl0sIm1hcHBpbmdzIjoiQUFBQSxJQUFJQSxJQUFNLFdBQ04sU0FBU0MsSUFBS0QsS0FDVixPQUFPQSxJQUdYLE9BQU9DIn0=",
+                "//# sourceMappingURL=data:application/json;charset=utf-8;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbInRlc3QvaW5wdXQvaXNzdWUtMTMyMy9zYW1wbGUuanMiXSwibmFtZXMiOlsiYmFyIiwiZm9vIl0sIm1hcHBpbmdzIjoiQUFBQSxJQUFJQSxJQUFNLFdBQ04sU0FBU0MsSUFBS0QsS0FDVixPQUFPQSxJQUdYLE9BQU9DLElBTEQifQ==",
                 "",
             ].join("\n"));
             assert.strictEqual(stderr, "WARN: inline source map not found\n");
@@ -686,8 +686,8 @@ describe("bin/uglifyjs", function () {
             done();
         });
     });
-    it("Should work with --mangle reserved=[]", function (done) {
-        var command = uglifyjscmd + ' test/input/issue-505/input.js -m reserved=[callback]';
+    it("Should work with --mangle reserved=[]", function(done) {
+        var command = uglifyjscmd + " test/input/issue-505/input.js -m reserved=[callback]";
 
         exec(command, function (err, stdout) {
             if (err) throw err;
@@ -696,8 +696,8 @@ describe("bin/uglifyjs", function () {
             done();
         });
     });
-    it("Should work with --mangle reserved=false", function (done) {
-        var command = uglifyjscmd + ' test/input/issue-505/input.js -m reserved=false';
+    it("Should work with --mangle reserved=false", function(done) {
+        var command = uglifyjscmd + " test/input/issue-505/input.js -m reserved=false";
 
         exec(command, function (err, stdout) {
             if (err) throw err;
@@ -706,4 +706,22 @@ describe("bin/uglifyjs", function () {
             done();
         });
     });
+    it("Should fail with --mangle-props reserved=[in]", function(done) {
+        var command = uglifyjscmd + " test/input/issue-505/input.js --mangle-props reserved=[in]";
+        exec(command, function (err, stdout, stderr) {
+            assert.ok(err);
+            assert.strictEqual(stdout, "");
+            assert.ok(/^Supported options:\n[\s\S]*?\nERROR: `reserved=\[in]` is not a supported option/.test(stderr), stderr);
+            done();
+        });
+    });
+    it("Should fail with --define a-b", function(done) {
+        var command = uglifyjscmd + " test/input/issue-505/input.js --define a-b";
+        exec(command, function (err, stdout, stderr) {
+            assert.ok(err);
+            assert.strictEqual(stdout, "");
+            assert.strictEqual(stderr, "Error parsing arguments for 'define': a-b\n");
+            done();
+        });
+    });
 });

test/mocha/let.js

@@ -2,16 +2,17 @@ var Uglify = require('../../');
 var assert = require("assert");
 
 describe("let", function() {
-    it("Should not produce reserved keywords as variable name in mangle", function(done) {
-        this.timeout(10000);
-
+    this.timeout(30000);
+    it("Should not produce reserved keywords as variable name in mangle", 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 result = Uglify.minify(s, {compress: false});
+        var result = Uglify.minify(s, {
+            compress: false
+        }).code;
 
         // Verify that select keywords and reserved keywords not produced
         [
@@ -19,7 +20,7 @@ describe("let", function() {
             "let",
             "var",
         ].forEach(function(name) {
-            assert.strictEqual(result.code.indexOf("var " + name + "="), -1);
+            assert.strictEqual(result.indexOf("var " + name + "="), -1);
         });
 
         // Verify that the variable names that appeared immediately before
@@ -30,9 +31,27 @@ describe("let", function() {
             "eet", "fet",
             "rar", "oar",
         ].forEach(function(name) {
-            assert.ok(result.code.indexOf("var " + name + "=") >= 0);
+            assert.notStrictEqual(result.indexOf("var " + name + "="), -1);
+        });
+    });
+    it("Should quote mangled properties that are reserved keywords", function() {
+        var s = '"rrrrrnnnnniiiiiaaaaa";';
+        for (var i = 0; i < 18000; i++) {
+            s += "v.b" + i + ";";
+        }
+        var result = Uglify.minify(s, {
+            compress: false,
+            ie8: true,
+            mangle: {
+                properties: true,
+            }
+        }).code;
+        [
+            "in",
+            "var",
+        ].forEach(function(name) {
+            assert.notStrictEqual(result.indexOf(name), -1);
+            assert.notStrictEqual(result.indexOf('v["' + name + '"]'), -1);
         });
-
-        done();
     });
 });

test/mocha/lhs-expressions.js

@@ -253,13 +253,19 @@ describe("Left-hand side expressions", function () {
         // Multiple spreads are not allowed in destructuring array
         expect("[...a, ...b] = [1, 2, 3, 4]", "Spread must the be last element in destructuring array");
 
-        // Spread in obvious object pattern
-        expect("({...a} = foo)", "Unexpected token: expand (...)");
+        // Array spread must be last in destructuring declaration
+        expect("let [ ...x, a ] = o;", "Rest element must be last element");
+
+        // Only one spread per destructuring array declaration
+        expect("let [ a, ...x, ...y ] = o;", "Rest element must be last element");
 
         // Spread in block should not be allowed
         expect("{...a} = foo", "Unexpected token: expand (...)");
 
-        // Not in standard yet
-        expect("let foo = {bar: 42}, bar; bar = {...foo}", "Unexpected token: expand (...)");
+        // Object spread must be last in destructuring declaration
+        expect("let { ...x, a } = o;", "Rest element must be last element");
+
+        // Only one spread per destructuring declaration
+        expect("let { a, ...x, ...y } = o;", "Rest element must be last element");
     });
 });

test/mocha/minify.js

@@ -124,6 +124,17 @@ describe("minify", function() {
             assert.strictEqual(result.code,
                     'a["foo"]="bar",a.a="red",x={"bar":10};');
         });
+        it("Should not mangle quoted property within dead code", function() {
+            var result = Uglify.minify('({ "keep": 1 }); g.keep = g.change;', {
+                mangle: {
+                    properties: {
+                        keep_quoted: true
+                    }
+                }
+            });
+            if (result.error) throw result.error;
+            assert.strictEqual(result.code, "g.keep=g.g;");
+        });
     });
 
     describe("inSourceMap", function() {
@@ -280,4 +291,34 @@ describe("minify", function() {
             assert.strictEqual(result.code, "alert({bar:42});");
         });
     });
+
+    describe("duplicated block-scoped declarations", function() {
+        [
+            "let a=1;let a=2;",
+            "let a=1;var a=2;",
+            "var a=1;let a=2;",
+            "let[a]=[1];var a=2;",
+            "let a=1;var[a]=[2];",
+            "let[a]=[1];var[a]=[2];",
+            "const a=1;const a=2;",
+            "const a=1;var a=2;",
+            "var a=1;const a=2;",
+            "const[a]=[1];var a=2;",
+            "const a=1;var[a]=[2];",
+            "const[a]=[1];var[a]=[2];",
+        ].forEach(function(code) {
+            it(code, function() {
+                var result = Uglify.minify(code, {
+                    compress: false,
+                    mangle: false
+                });
+                assert.strictEqual(result.error, undefined);
+                assert.strictEqual(result.code, code);
+                result = Uglify.minify(code);
+                var err = result.error;
+                assert.ok(err instanceof Error);
+                assert.strictEqual(err.stack.split(/\n/)[0], "SyntaxError: a redeclared");
+            });
+        });
+    });
 });

test/mocha/string-literal.js

@@ -61,9 +61,9 @@ describe("String literals", function() {
         var tests = [
             ['"\\76";', ';">";'],
             ['"\\0"', '"\\0";'],
-            ['"\\08"', '"\\08";'],
-            ['"\\008"', '"\\08";'],
-            ['"\\0008"', '"\\08";'],
+            ['"\\08"', '"\\x008";'],
+            ['"\\008"', '"\\x008";'],
+            ['"\\0008"', '"\\x008";'],
             ['"use strict" === "use strict";\n"\\76";', '"use strict"==="use strict";">";'],
             ['"use\\\n strict";\n"\\07";', ';"use strict";"\07";']
         ];
@@ -75,7 +75,44 @@ describe("String literals", function() {
     });
 
     it("Should not throw error when digit is 8 or 9", function() {
-        assert.equal(UglifyJS.parse('"use strict";"\\08"').print_to_string(), '"use strict";"\\08";');
-        assert.equal(UglifyJS.parse('"use strict";"\\09"').print_to_string(), '"use strict";"\\09";');
+        assert.equal(UglifyJS.parse('"use strict";"\\08"').print_to_string(), '"use strict";"\\x008";');
+        assert.equal(UglifyJS.parse('"use strict";"\\09"').print_to_string(), '"use strict";"\\x009";');
+    });
+
+    it("Should not unescape unpaired surrogates", function() {
+        var code = [];
+        for (var i = 0; i <= 0xF; i++) {
+            code.push("\\u000" + i.toString(16));
+        }
+        for (;i <= 0xFF; i++) {
+            code.push("\\u00" + i.toString(16));
+        }
+        for (;i <= 0xFFF; i++) {
+            code.push("\\u0" + i.toString(16));
+        }
+        for (; i <= 0xFFFF; i++) {
+            code.push("\\u" + i.toString(16));
+        }
+        code = '"' + code.join() + '"';
+        var normal = UglifyJS.minify(code, {
+            compress: false,
+            mangle: false,
+            output: {
+                ascii_only: false
+            }
+        });
+        if (normal.error) throw normal.error;
+        assert.ok(code.length > normal.code.length);
+        assert.strictEqual(eval(code), eval(normal.code));
+        var ascii = UglifyJS.minify(code, {
+            compress: false,
+            mangle: false,
+            output: {
+                ascii_only: false
+            }
+        });
+        if (ascii.error) throw ascii.error;
+        assert.ok(code.length > ascii.code.length);
+        assert.strictEqual(eval(code), eval(ascii.code));
     });
 });

test/mocha/unicode.js

@@ -1,4 +1,5 @@
 var assert = require("assert");
+var semver = require("semver");
 var uglify = require("../node");
 
 describe("Unicode", function() {
@@ -138,8 +139,34 @@ describe("Unicode", function() {
 
     it("Should parse raw characters correctly", function() {
         var ast = uglify.parse('console.log("\\udbff");');
-        assert.strictEqual(ast.print_to_string(), 'console.log("\udbff");');
+        assert.strictEqual(ast.print_to_string(), 'console.log("\\udbff");');
         ast = uglify.parse(ast.print_to_string());
-        assert.strictEqual(ast.print_to_string(), 'console.log("\udbff");');
+        assert.strictEqual(ast.print_to_string(), 'console.log("\\udbff");');
     });
+
+    if (semver.satisfies(process.version, ">=4")) {
+        it("Should not unescape unpaired surrogates", function() {
+            this.timeout(5000);
+            var code = [];
+            for (var i = 0; i <= 0x20001; i++) {
+                code.push("\\u{" + i.toString(16) + "}");
+            }
+            code = '"' + code.join() + '"';
+            [true, false].forEach(function(ascii_only) {
+                [5, 6].forEach(function(ecma) {
+                    var result = uglify.minify(code, {
+                        compress: false,
+                        mangle: false,
+                        output: {
+                            ascii_only: ascii_only
+                        },
+                        ecma: ecma
+                    });
+                    if (result.error) throw result.error;
+                    if (ecma > 5) assert.ok(code.length > result.code.length);
+                    assert.strictEqual(eval(code), eval(result.code));
+                });
+            });
+        });
+    }
 });

test/run-tests.js

@@ -111,18 +111,22 @@ function run_compress_tests() {
                 };
                 if (!options.warnings) options.warnings = true;
             }
+            if (test.mangle && test.mangle.properties && test.mangle.properties.keep_quoted) {
+                var quoted_props = test.mangle.properties.reserved;
+                if (!Array.isArray(quoted_props)) quoted_props = [];
+                test.mangle.properties.reserved = quoted_props;
+                U.reserve_quoted_keys(input, quoted_props);
+            }
             var cmp = new U.Compressor(options, true);
             var output = cmp.compress(input);
             output.figure_out_scope(test.mangle);
-            if (test.mangle || test.mangle_props) {
+            if (test.mangle) {
                 U.base54.reset();
                 output.compute_char_frequency(test.mangle);
-            }
-            if (test.mangle) {
                 output.mangle_names(test.mangle);
-            }
-            if (test.mangle_props) {
-                output = U.mangle_properties(output, test.mangle_props);
+                if (test.mangle.properties) {
+                    output = U.mangle_properties(output, test.mangle.properties);
+                }
             }
             output = make_code(output, output_options);
             if (expect != output) {