fix wording and formatting (#2512)

README.md

@@ -598,17 +598,17 @@ If you're using the `X-SourceMap` header instead, you can just omit `sourceMap.u
 
 ## Compress options
 
-- `booleans` (default: `true`) -- various optimizations for boolean context, for example `!!a
+- `booleans` (default: `true`) -- various optimizations for boolean context,
-  ? b : c → a ? b : c`
+  for example `!!a ? b : c → a ? b : c`
 
-- `cascade` (default: `true`) -- small optimization for sequences, transform `x, x` into `x`
+- `cascade` (default: `true`) -- small optimization for sequences, transform
-  and `x = something(), x` into `x = something()`
+  `x, x` into `x` and `x = something(), x` into `x = something()`
 
-- `collapse_vars` (default: `true`) -- Collapse single-use non-constant variables - side
+- `collapse_vars` (default: `true`) -- Collapse single-use non-constant variables,
-  effects permitting.
+  side effects permitting.
 
-- `comparisons` (default: `true`) -- apply certain optimizations to binary nodes, for example:
+- `comparisons` (default: `true`) -- apply certain optimizations to binary nodes,
-  `!(a <= b) → a > b` (only when `unsafe_comps`), attempts to negate binary
+  e.g. `!(a <= b) → a > b` (only when `unsafe_comps`), attempts to negate binary
   nodes, e.g. `a = !b && !c && !d && !e → a=!(b||c||d||e)` etc.
 
 - `conditionals` (default: `true`) -- apply optimizations for `if`-s and conditional
@@ -616,7 +616,7 @@ If you're using the `X-SourceMap` header instead, you can just omit `sourceMap.u
 
 - `dead_code` (default: `true`) -- remove unreachable code
 
-- `drop_console` (default: `false`) -- default `false`.  Pass `true` to discard calls to
+- `drop_console` (default: `false`) -- Pass `true` to discard calls to
   `console.*` functions. If you wish to drop a specific function call
   such as `console.info` and/or retain side effects from function arguments
   after dropping the function call then use `pure_funcs` instead.
@@ -625,7 +625,7 @@ If you're using the `X-SourceMap` header instead, you can just omit `sourceMap.u
 
 - `evaluate` (default: `true`) -- attempt to evaluate constant expressions
 
-- `expression` (default: `false`) -- default `false`.  Pass `true` to preserve completion values
+- `expression` (default: `false`) -- Pass `true` to preserve completion values
   from terminal statements without `return`, e.g. in bookmarklets.
 
 - `global_defs` (default: `{}`) -- see [conditional compilation](#conditional-compilation)
@@ -647,19 +647,18 @@ If you're using the `X-SourceMap` header instead, you can just omit `sourceMap.u
 
 - `join_vars` (default: `true`) -- join consecutive `var` statements
 
-- `keep_fargs` (default: `true`) -- default `true`.  Prevents the
+- `keep_fargs` (default: `true`) -- Prevents the compressor from discarding unused
-  compressor from discarding unused function arguments.  You need this
+  function arguments.  You need this for code which relies on `Function.length`.
-  for code which relies on `Function.length`.
 
 - `keep_fnames` (default: `false`) -- Pass `true` to prevent the
   compressor from discarding function names.  Useful for code relying on
   `Function.prototype.name`. See also: the `keep_fnames` [mangle option](#mangle).
 
-- `keep_infinity` (default: `false`) -- default `false`. Pass `true` to prevent `Infinity` from
+- `keep_infinity` (default: `false`) -- Pass `true` to prevent `Infinity` from
   being compressed into `1/0`, which may cause performance issues on Chrome.
 
-- `loops` (default: `true`) -- optimizations for `do`, `while` and `for` loops when we can
+- `loops` (default: `true`) -- optimizations for `do`, `while` and `for` loops
-  statically determine the condition
+  when we can statically determine the condition.
 
 - `negate_iife` (default: `true`) -- negate "Immediately-Called Function Expressions"
   where the return value is discarded, to avoid the parens that the
@@ -707,21 +706,22 @@ If you're using the `X-SourceMap` header instead, you can just omit `sourceMap.u
   occasions the default sequences limit leads to very slow compress times in which
   case a value of `20` or less is recommended.
 
-- `side_effects` (default: `true`) -- default `true`. Pass `false` to disable potentially dropping
+- `side_effects` (default: `true`) -- Pass `false` to disable potentially dropping
   functions marked as "pure".  A function call is marked as "pure" if a comment
   annotation `/*@__PURE__*/` or `/*#__PURE__*/` immediately precedes the call. For
   example: `/*@__PURE__*/foo();`
 
 - `switches` (default: `true`) -- de-duplicate and remove unreachable `switch` branches
 
-- `toplevel` (default: `false`) -- drop unreferenced functions (`"funcs"`) and/or variables (`"vars"`)
+- `toplevel` (default: `false`) -- drop unreferenced functions (`"funcs"`) and/or
-  in the top level scope (`false` by default, `true` to drop both unreferenced
+  variables (`"vars"`) in the top level scope (`false` by default, `true` to drop
-  functions and variables)
+  both unreferenced functions and variables)
 
-- `top_retain` (default: `null`) -- prevent specific toplevel functions and variables from `unused`
+- `top_retain` (default: `null`) -- prevent specific toplevel functions and
-  removal (can be array, comma-separated, RegExp or function. Implies `toplevel`)
+  variables from `unused` removal (can be array, comma-separated, RegExp or
+  function. Implies `toplevel`)
 
-- `typeofs` (default: `true`) -- default `true`.  Transforms `typeof foo == "undefined"` into
+- `typeofs` (default: `true`) -- Transforms `typeof foo == "undefined"` into
   `foo === void 0`.  Note: recommend to set this value to `false` for IE10 and
   earlier versions due to known issues.
 
@@ -746,25 +746,25 @@ If you're using the `X-SourceMap` header instead, you can just omit `sourceMap.u
 - `unsafe_regexp` (default: `false`) -- enable substitutions of variables with
   `RegExp` values the same way as if they are constants.
 
-- `unused` (default: `true`) -- drop unreferenced functions and variables (simple direct variable
+- `unused` (default: `true`) -- drop unreferenced functions and variables (simple
-  assignments do not count as references unless set to `"keep_assign"`)
+  direct variable assignments do not count as references unless set to `"keep_assign"`)
 
-- `warnings` (default: `false`) -- display warnings when dropping unreachable code or unused
+- `warnings` (default: `false`) -- display warnings when dropping unreachable
-  declarations etc.
+  code or unused declarations etc.
 
 ## Mangle options
 
-- `eval` (default `false`). Pass `true` to mangle names visible in scopes
+- `eval` (default `false`) -- Pass `true` to mangle names visible in scopes
   where `eval` or `with` are used.
 
-- `keep_fnames` (default `false`).  Pass `true` to not mangle function names.
+- `keep_fnames` (default `false`) -- Pass `true` to not mangle function names.
   Useful for code relying on `Function.prototype.name`. See also: the `keep_fnames`
   [compress option](#compress-options).
 
-- `reserved` (default `[]`). Pass an array of identifiers that should be
+- `reserved` (default `[]`) -- Pass an array of identifiers that should be
   excluded from mangling. Example: `["foo", "bar"]`.
 
-- `toplevel` (default `false`). Pass `true` to mangle names declared in the
+- `toplevel` (default `false`) -- Pass `true` to mangle names declared in the
   top level scope.
 
 Examples: