UglifyJS Plugin
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UglifyJS Webpack Plugin

This plugin uses UglifyJS v3 (`uglify-es`) to minify your JavaScript

ℹ️ webpack < v4.0.0 currently contains v0.4.6 of this plugin under webpack.optimize.UglifyJsPlugin as an alias. For usage of the latest version (v1.0.0), please follow the instructions below. Aliasing v1.0.0 as webpack.optimize.UglifyJsPlugin is scheduled for webpack v4.0.0

Install

npm i -D uglifyjs-webpack-plugin

Usage

webpack.config.js

const UglifyJsPlugin = require('uglifyjs-webpack-plugin')

module.exports = {
  //...
  optimization: {
    minimizer: [
      new UglifyJsPlugin()
    ]
  }
}

Options

Name Type Default Description
test {RegExp|Array<RegExp>} /\.js$/i Test to match files against
include {RegExp|Array<RegExp>} undefined Files to include
exclude {RegExp|Array<RegExp>} undefined Files to exclude
cache {Boolean|String} false Enable file caching
cacheKeys {Function(defaultCacheKeys, file) -> {Object}} defaultCacheKeys => defaultCacheKeys Allows you to override default cache keys
parallel {Boolean|Number} false Use multi-process parallel running to improve the build speed
sourceMap {Boolean} false Use source maps to map error message locations to modules (This slows down the compilation) ⚠️ cheap-source-map options don't work with this plugin
minify {Function} undefined Allows you to override default minify function
uglifyOptions {Object} {...defaults} uglify Options
extractComments {Boolean|RegExp|Function<(node, comment) -> {Boolean|Object}>} false Whether comments shall be extracted to a separate file, (see details (webpack >= 2.3.0)
warningsFilter {Function(source) -> {Boolean}} () => true Allow to filter uglify warnings

test

webpack.config.js

[
  new UglifyJsPlugin({
    test: /\.js($|\?)/i
  })
]

include

webpack.config.js

[
  new UglifyJsPlugin({
    include: /\/includes/
  })
]

exclude

webpack.config.js

[
  new UglifyJsPlugin({
    exclude: /\/excludes/
  })
]

cache

If you use your own minify function please read the minify section for cache invalidation correctly.

{Boolean}

webpack.config.js

[
  new UglifyJsPlugin({
    cache: true
  })
]

Enable file caching. Default path to cache directory: node_modules/.cache/uglifyjs-webpack-plugin.

{String}

webpack.config.js

[
  new UglifyJsPlugin({
    cache: 'path/to/cache'
  })
]

Path to cache directory.

cacheKeys

webpack.config.js

[
  new UglifyJsPlugin({
    cache: true,
    cacheKeys: (defaultCacheKeys, file) => {
      defaultCacheKeys.myCacheKey = 'myCacheKeyValue';
      
      return defaultCacheKeys;
    },
  })
]

Allows you to override default cache keys.

Default keys:

{
  'uglify-es': versions.uglify, // uglify version
  'uglifyjs-webpack-plugin': versions.plugin, // plugin version
  'uglifyjs-webpack-plugin-options': this.options, // plugin options
  path: compiler.outputPath ? `${compiler.outputPath}/${file}` : file, // asset path
  hash: crypto.createHash('md4').update(input).digest('hex'), // source file hash
}

parallel

{Boolean}

webpack.config.js

[
  new UglifyJsPlugin({
    parallel: true
  })
]

Enable parallelization. Default number of concurrent runs: os.cpus().length - 1.

{Number}

webpack.config.js

[
  new UglifyJsPlugin({
    parallel: 4
  })
]

Number of concurrent runs.

ℹ️ Parallelization can speedup your build significantly and is therefore highly recommended

sourceMap

If you use your own minify function please read the minify section for handling source maps correctly.

webpack.config.js

[
  new UglifyJsPlugin({
    sourceMap: true
  })
]

⚠️ cheap-source-map options don't work with this plugin

minify

webpack.config.js

[
  new UglifyJsPlugin({
     minify(file, sourceMap) {
       const extractedComments = [];

       // Custom logic for extract comments

       const { error, map, code, warnings } = minify(
         file,
         { /* Your options for minification */ },
       );

       return { error, map, code, warnings, extractedComments };
      }
  })
]

By default plugin uses uglify-es package.

Examples:

uglify-js

npm i -D uglify-js

webpack.config.js

[
  new UglifyJsPlugin({
    // Uncomment lines below for cache invalidation correctly
    // cache: true,
    // cacheKeys(defaultCacheKeys) {
    //   return Object.assign(
    //     {},
    //     defaultCacheKeys,
    //     { 'uglify-js': require('uglify-js/package.json').version },
    //   );
    // },
    minify(file, sourceMap) {
      // https://github.com/mishoo/UglifyJS2#minify-options
      const uglifyJsOptions = { /* your `uglify-js` package options */ };

      if (sourceMap) {
        uglifyJsOptions.sourceMap = {
          content: sourceMap,
        };
      }

      return require('uglify-js').minify(file, uglifyJsOptions);
    }
  })
]

terser

npm i -D terser

webpack.config.js

[
  new UglifyJsPlugin({
    // Uncomment lines below for cache invalidation correctly
    // cache: true,
    // cacheKeys(defaultCacheKeys) {
    //   return Object.assign(
    //     {},
    //     defaultCacheKeys,
    //     { terser: require('terser/package.json').version },
    //   );
    // },
    minify(file, sourceMap) {
      // https://github.com/fabiosantoscode/terser#minify-options
      const terserOptions = { /* your `terser` package options */ };

      if (sourceMap) {
        terserOption.sourceMap = {
          content: sourceMap,
        };
      }

      return require('terser').minify(file, terserOptions);
    }
  })
]

uglifyOptions

Name Type Default Description
ecma {Number} undefined Supported ECMAScript Version (5, 6, 7 or 8). Affects parse, compress && output options
warnings {Boolean} false Display Warnings
parse {Object} {} Additional Parse Options
compress {Boolean|Object} true Additional Compress Options
mangle {Boolean|Object} {inline: false} Enable Name Mangling (See Mangle Properties for advanced setups, use with ⚠️)
output {Object} {comments: extractComments ? false : /^\**!|@preserve|@license|@cc_on/,} Additional Output Options (The defaults are optimized for best compression)
toplevel {Boolean} false Enable top level variable and function name mangling and to drop unused variables and functions
nameCache {Object} null Enable cache of mangled variable and property names across multiple invocations
ie8 {Boolean} false Enable IE8 Support
keep_classnames {Boolean} undefined Enable prevent discarding or mangling of class names
keep_fnames {Boolean} false Enable prevent discarding or mangling of function names. Useful for code relying on Function.prototype.name. If the top level minify option keep_classnames is undefined it will be overriden with the value of the top level minify option keep_fnames
safari10 {Boolean} false Enable work around Safari 10/11 bugs in loop scoping and await

webpack.config.js

[
  new UglifyJsPlugin({
    uglifyOptions: {
      ecma: 8,
      warnings: false,
      parse: {...options},
      compress: {...options},
      mangle: {
        ...options,
        properties: {
          // mangle property options
        }
      },
      output: {
        comments: false,
        beautify: false,
        ...options
      },
      toplevel: false,
      nameCache: null,
      ie8: false,
      keep_classnames: undefined,
      keep_fnames: false,
      safari10: false,
    }
  })
]

extractComments

{Boolean}

All comments that normally would be preserved by the comments option will be moved to a separate file. If the original file is named foo.js, then the comments will be stored to foo.js.LICENSE.

{RegExp|String} or {Function<(node, comment) -> {Boolean}>}

All comments that match the given expression (resp. are evaluated to true by the function) will be extracted to the separate file. The comments option specifies whether the comment will be preserved, i.e. it is possible to preserve some comments (e.g. annotations) while extracting others or even preserving comments that have been extracted.

{Object}

Name Type Default Description
condition {Regex|Function} `` Regular Expression or function (see previous point)
filename {String|Function} ${file}.LICENSE The file where the extracted comments will be stored. Can be either a {String} or a {Function<(string) -> {String}>}, which will be given the original filename. Default is to append the suffix .LICENSE to the original filename
banner {Boolean|String|Function} /*! For license information please see ${filename}.js.LICENSE */ The banner text that points to the extracted file and will be added on top of the original file. Can be false (no banner), a {String}, or a {Function<(string) -> {String} that will be called with the filename where extracted comments have been stored. Will be wrapped into comment

warningsFilter

webpack.config.js

[
  new UglifyJsPlugin({
    warningsFilter: (src) => true
  })
]

Maintainers


Steven Hargrove

Juho Vepsäläinen

Joshua Wiens

Michael Ciniawsky

Alexander Krasnoyarov