UglifyJS
JavaScript parser / mangler / compressor / beautifier toolkit
Install / Use
/learn @mishoo/UglifyJSREADME
UglifyJS 3
UglifyJS is a JavaScript parser, minifier, compressor and beautifier toolkit.
Note:
uglify-jssupports JavaScript and most language features in ECMAScript.- For more exotic parts of ECMAScript, process your source file with transpilers
like Babel before passing onto
uglify-js. uglify-js@3has a simplified API and CLI that is not backwards compatible withuglify-js@2.
Install
First make sure you have installed the latest version of node.js (You may need to restart your computer after this step).
From NPM for use as a command line app:
npm install uglify-js -g
From NPM for programmatic use:
npm install uglify-js
Command line usage
uglifyjs [input files] [options]
UglifyJS can take multiple input files. It's recommended that you pass the input files first, then pass the options. UglifyJS will parse input files in sequence and apply any compression options. The files are parsed in the same global scope, that is, a reference from a file to some variable/function declared in another file will be matched properly.
If no input file is specified, UglifyJS will read from STDIN.
If you wish to pass your options before the input files, separate the two with a double dash to prevent input files being used as option arguments:
uglifyjs --compress --mangle -- input.js
Command line options
-h, --help Print usage information.
`--help options` for details on available options.
-V, --version Print version number.
-p, --parse <options> Specify parser options:
`acorn` Use Acorn for parsing.
`bare_returns` Allow return outside of functions.
Useful when minifying CommonJS
modules and Userscripts that may
be anonymous function wrapped (IIFE)
by the .user.js engine `caller`.
`spidermonkey` Assume input files are SpiderMonkey
AST format (as JSON).
-c, --compress [options] Enable compressor/specify compressor options:
`pure_funcs` List of functions that can be safely
removed when their return values are
not used.
-m, --mangle [options] Mangle names/specify mangler options:
`reserved` List of names that should not be mangled.
--mangle-props [options] Mangle properties/specify mangler options:
`builtins` Mangle property names that overlaps
with standard JavaScript globals.
`debug` Add debug prefix and suffix.
`domprops` Mangle property names that overlaps
with DOM properties.
`globals` Mangle variable access via global object.
`keep_quoted` Only mangle unquoted properties.
`regex` Only mangle matched property names.
`reserved` List of names that should not be mangled.
-b, --beautify [options] Beautify output/specify output options:
`beautify` Enabled with `--beautify` by default.
`preamble` Preamble to prepend to the output. You
can use this to insert a comment, for
example for licensing information.
This will not be parsed, but the source
map will adjust for its presence.
`quote_style` Quote style:
0 - auto
1 - single
2 - double
3 - original
`wrap_iife` Wrap IIFEs in parentheses. Note: you may
want to disable `negate_iife` under
compressor options.
-O, --output-opts [options] Specify output options (`beautify` disabled by default).
-o, --output <file> Output file path (default STDOUT). Specify `ast` or
`spidermonkey` to write UglifyJS or SpiderMonkey AST
as JSON to STDOUT respectively.
--annotations Process and preserve comment annotations.
(`/*@__PURE__*/` or `/*#__PURE__*/`)
--no-annotations Ignore and discard comment annotations.
--comments [filter] Preserve copyright comments in the output. By
default this works like Google Closure, keeping
JSDoc-style comments that contain "@license" or
"@preserve". You can optionally pass one of the
following arguments to this flag:
- "all" to keep all comments
- a valid JS RegExp like `/foo/` or `/^!/` to
keep only matching comments.
Note that currently not *all* comments can be
kept when compression is on, because of dead
code removal or cascading statements into
sequences.
--config-file <file> Read `minify()` options from JSON file.
-d, --define <expr>[=value] Global definitions.
-e, --enclose [arg[:value]] Embed everything in a big function, with configurable
argument(s) & value(s).
--expression Parse a single expression, rather than a program
(for parsing JSON).
--ie Support non-standard Internet Explorer.
Equivalent to setting `ie: true` in `minify()`
for `compress`, `mangle` and `output` options.
By default UglifyJS will not try to be IE-proof.
--keep-fargs Do not mangle/drop function arguments.
--keep-fnames Do not mangle/drop function names. Useful for
code relying on Function.prototype.name.
--module Process input as ES module (implies --toplevel)
--no-module Avoid optimizations which may alter runtime behavior
under prior versions of JavaScript.
--name-cache <file> File to hold mangled name mappings.
--self Build UglifyJS as a library (implies --wrap UglifyJS)
--source-map [options] Enable source map/specify source map options:
`base` Path to compute relative paths from input files.
`content` Input source map, useful if you're compressing
JS that was generated from some other original
code. Specify "inline" if the source map is
included within the sources.
`filename` Filename and/or location of the output source
(sets `file` attribute in source map).
`includeSources` Pass this flag if you want to include
the content of source files in the
source map as sourcesContent property.
`names` Include symbol names in the source map.
`root` Path to the original source to be included in
the source map.
`url` If specified, path to the source map to append in
`//# sourceMappingURL`.
--timings Display operations run time on STDERR.
--toplevel Compress and/or mangle variables in top level scope.
--v8 Support non-standard Chrome & Node.js
Equivalent to setting `v8: true` in `minify()`
for `mangle` and `output` options.
By default UglifyJS will not try to be v8-proof.
--verbose Print diagnostic messages.
--warn Print warning messages.
--webkit Support non-standard Safari/Webkit.
Equivalent to setting `webkit: true` in `minify()`
for `compress`, `mangle` and `output` options.
By default UglifyJS will not try to be Safari-proof.
--wrap <name> Embed everything in a big function, making the
“exports” and “global” variables available. You
need to pass an argument to this option to
specify the name that your module will take
when included in, say, a bro
