uglifyjs-webpack-plugin
Advanced tools
The uglifyjs-webpack-plugin is a plugin for Webpack that uses UglifyJS to minify JavaScript files. It helps in reducing the size of JavaScript files by removing unnecessary characters, comments, and whitespace, and by optimizing the code.
Basic Minification
This feature allows you to perform basic minification of JavaScript files using UglifyJS. The code sample demonstrates how to configure the plugin in a Webpack configuration file to minimize the output JavaScript files.
const UglifyJsPlugin = require('uglifyjs-webpack-plugin');
module.exports = {
optimization: {
minimizer: [new UglifyJsPlugin()]
}
};Custom UglifyJS Options
This feature allows you to customize the UglifyJS options. The code sample shows how to configure the plugin to remove console statements from the output JavaScript files.
const UglifyJsPlugin = require('uglifyjs-webpack-plugin');
module.exports = {
optimization: {
minimizer: [
new UglifyJsPlugin({
uglifyOptions: {
compress: {
drop_console: true,
},
},
}),
],
},
};Source Map Support
This feature enables source map support, which helps in debugging minified code. The code sample demonstrates how to configure the plugin to generate source maps for the minified JavaScript files.
const UglifyJsPlugin = require('uglifyjs-webpack-plugin');
module.exports = {
devtool: 'source-map',
optimization: {
minimizer: [
new UglifyJsPlugin({
sourceMap: true,
}),
],
},
};The terser-webpack-plugin is a Webpack plugin that uses Terser to minify JavaScript files. Terser is a fork of UglifyJS with better support for ES6+ syntax. It is often preferred over uglifyjs-webpack-plugin for modern JavaScript projects due to its better handling of newer JavaScript features.
The babel-minify-webpack-plugin is a Webpack plugin that uses Babel Minify (babel-minify) to minify JavaScript files. It is designed to work seamlessly with Babel and offers a wide range of minification options. It is a good alternative to uglifyjs-webpack-plugin, especially if you are already using Babel in your project.
The closure-webpack-plugin is a Webpack plugin that uses Google Closure Compiler to minify JavaScript files. It offers advanced optimizations and is capable of performing aggressive code transformations. It is suitable for large projects that require high levels of optimization and code analysis.
This plugin uses uglify-js to minify your JavaScript.
This module requires a minimum of Node v6.9.0 and Webpack v4.0.0.
To begin, you'll need to install uglifyjs-webpack-plugin:
$ npm install uglifyjs-webpack-plugin --save-dev
Then add the plugin to your webpack config. For example:
webpack.config.js
const UglifyJsPlugin = require('uglifyjs-webpack-plugin');
module.exports = {
optimization: {
minimizer: [new UglifyJsPlugin()],
},
};
And run webpack via your preferred method.
testType: String|RegExp|Array<String|RegExp>
Default: /\.js(\?.*)?$/i
Test to match files against.
webpack.config.js
module.exports = {
optimization: {
minimizer: [
new UglifyJsPlugin({
test: /\.js(\?.*)?$/i,
}),
],
},
};
includeType: String|RegExp|Array<String|RegExp>
Default: undefined
Files to include.
webpack.config.js
module.exports = {
optimization: {
minimizer: [
new UglifyJsPlugin({
include: /\/includes/,
}),
],
},
};
excludeType: String|RegExp|Array<String|RegExp>
Default: undefined
Files to exclude.
webpack.config.js
module.exports = {
optimization: {
minimizer: [
new UglifyJsPlugin({
exclude: /\/excludes/,
}),
],
},
};
chunkFilterType: Function<(chunk) -> boolean>
Default: () => true
Allowing to filter which chunks should be uglified (by default all chunks are uglified).
Return true to uglify the chunk, false otherwise.
webpack.config.js
module.exports = {
optimization: {
minimizer: [
new UglifyJsPlugin({
chunkFilter: (chunk) => {
// Exclude uglification for the `vendor` chunk
if (chunk.name === 'vendor') {
return false;
}
return true;
},
}),
],
},
};
cacheType: Boolean|String
Default: false
Enable file caching.
Default path to cache directory: node_modules/.cache/uglifyjs-webpack-plugin.
ℹ️ If you use your own
minifyfunction please read theminifysection for cache invalidation correctly.
BooleanEnable/disable file caching.
webpack.config.js
module.exports = {
optimization: {
minimizer: [
new UglifyJsPlugin({
cache: true,
}),
],
},
};
StringEnable file caching and set path to cache directory.
webpack.config.js
webpack.config.js
module.exports = {
optimization: {
minimizer: [
new UglifyJsPlugin({
cache: 'path/to/cache',
}),
],
},
};
cacheKeysType: Function<(defaultCacheKeys, file) -> Object>
Default: defaultCacheKeys => defaultCacheKeys
Allows you to override default cache keys.
Default cache keys:
({
'uglify-js': require('uglify-js/package.json').version, // uglify version
'uglifyjs-webpack-plugin': require('../package.json').version, // 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
});
webpack.config.js
module.exports = {
optimization: {
minimizer: [
new UglifyJsPlugin({
cache: true,
cacheKeys: (defaultCacheKeys, file) => {
defaultCacheKeys.myCacheKey = 'myCacheKeyValue';
return defaultCacheKeys;
},
}),
],
},
};
parallelType: Boolean|Number
Default: false
Use multi-process parallel running to improve the build speed.
Default number of concurrent runs: os.cpus().length - 1.
ℹ️ Parallelization can speedup your build significantly and is therefore highly recommended.
BooleanEnable/disable multi-process parallel running.
webpack.config.js
module.exports = {
optimization: {
minimizer: [
new UglifyJsPlugin({
parallel: true,
}),
],
},
};
NumberEnable multi-process parallel running and set number of concurrent runs.
webpack.config.js
module.exports = {
optimization: {
minimizer: [
new UglifyJsPlugin({
parallel: 4,
}),
],
},
};
sourceMapType: Boolean
Default: false
Use source maps to map error message locations to modules (this slows down the compilation).
If you use your own minify function please read the minify section for handling source maps correctly.
⚠️
cheap-source-mapoptions don't work with this plugin.
webpack.config.js
module.exports = {
optimization: {
minimizer: [
new UglifyJsPlugin({
sourceMap: true,
}),
],
},
};
minifyType: Function
Default: undefined
Allows you to override default minify function. By default plugin uses uglify-js package. Useful for using and testing unpublished versions or forks.
⚠️ Always use
requireinsideminifyfunction whenparalleloption enabled.
webpack.config.js
module.exports = {
optimization: {
minimizer: [
new UglifyJsPlugin({
minify(file, sourceMap) {
const extractedComments = [];
// Custom logic for extract comments
const { error, map, code, warnings } = require('uglify-module') // Or require('./path/to/uglify-module')
.minify(file, {
/* Your options for minification */
});
return { error, map, code, warnings, extractedComments };
},
}),
],
},
};
uglifyOptionsType: Object
Default: default
UglifyJS minify options.
webpack.config.js
module.exports = {
optimization: {
minimizer: [
new UglifyJsPlugin({
uglifyOptions: {
warnings: false,
parse: {},
compress: {},
mangle: true, // Note `mangle.properties` is `false` by default.
output: null,
toplevel: false,
nameCache: null,
ie8: false,
keep_fnames: false,
},
}),
],
},
};
extractCommentsType: Boolean|String|RegExp|Function<(node, comment) -> Boolean|Object>
Default: false
Whether comments shall be extracted to a separate file, (see details).
By default extract only comments using /^\**!|@preserve|@license|@cc_on/i regexp condition and remove remaining comments.
If the original file is named foo.js, then the comments will be stored to foo.js.LICENSE.
The uglifyOptions.output.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.
BooleanEnable/disable extracting comments.
webpack.config.js
module.exports = {
optimization: {
minimizer: [
new UglifyJsPlugin({
extractComments: true,
}),
],
},
};
StringExtract all or some (use /^\**!|@preserve|@license|@cc_on/i RegExp) comments.
webpack.config.js
module.exports = {
optimization: {
minimizer: [
new UglifyJsPlugin({
extractComments: 'all',
}),
],
},
};
RegExpAll comments that match the given expression will be extracted to the separate file.
webpack.config.js
module.exports = {
optimization: {
minimizer: [
new UglifyJsPlugin({
extractComments: /@extract/i,
}),
],
},
};
Function<(node, comment) -> Boolean>All comments that match the given expression will be extracted to the separate file.
webpack.config.js
module.exports = {
optimization: {
minimizer: [
new UglifyJsPlugin({
extractComments: function(astNode, comment) {
if (/@extract/i.test(comment.value)) {
return true;
}
return false;
},
}),
],
},
};
ObjectAllow to customize condition for extract comments, specify extracted file name and banner.
webpack.config.js
module.exports = {
optimization: {
minimizer: [
new UglifyJsPlugin({
extractComments: {
condition: /^\**!|@preserve|@license|@cc_on/i,
filename(file) {
return `${file}.LICENSE`;
},
banner(licenseFile) {
return `License information can be found in ${licenseFile}`;
},
},
}),
],
},
};
conditionType: Boolean|String|RegExp|Function<(node, comment) -> Boolean|Object>
Condition what comments you need extract.
webpack.config.js
module.exports = {
optimization: {
minimizer: [
new UglifyJsPlugin({
extractComments: {
condition: 'some',
filename(file) {
return `${file}.LICENSE`;
},
banner(licenseFile) {
return `License information can be found in ${licenseFile}`;
},
},
}),
],
},
};
filenameType: Regex|Function<(string) -> String>
Default: ${file}.LICENSE
The file where the extracted comments will be stored.
Default is to append the suffix .LICENSE to the original filename.
webpack.config.js
module.exports = {
optimization: {
minimizer: [
new UglifyJsPlugin({
extractComments: {
condition: /^\**!|@preserve|@license|@cc_on/i,
filename: 'extracted-comments.js',
banner(licenseFile) {
return `License information can be found in ${licenseFile}`;
},
},
}),
],
},
};
bannerType: Boolean|String|Function<(string) -> String>
Default: /*! For license information please see ${commentsFile} */
The banner text that points to the extracted file and will be added on top of the original file.
Can be false (no banner), a String, or a Function<(string) -> String> that will be called with the filename where extracted comments have been stored.
Will be wrapped into comment.
webpack.config.js
module.exports = {
optimization: {
minimizer: [
new UglifyJsPlugin({
extractComments: {
condition: true,
filename(file) {
return `${file}.LICENSE`;
},
banner(commentsFile) {
return `My custom banner about license information ${commentsFile}`;
},
},
}),
],
},
};
warningsFilterType: Function<(warning, source) -> Boolean>
Default: () => true
Allow to filter uglify-js warnings.
Return true to keep the warning, false otherwise.
webpack.config.js
module.exports = {
optimization: {
minimizer: [
new UglifyJsPlugin({
warningsFilter: (warning, source) => {
if (/Dropping unreachable code/i.test(warning)) {
return true;
}
if (/filename\.js/i.test(source)) {
return true;
}
return false;
},
}),
],
},
};
Enable cache and multi-process parallel running.
webpack.config.js
module.exports = {
optimization: {
minimizer: [
new UglifyJsPlugin({
cache: true,
parallel: true,
}),
],
},
};
Extract all legal comments (i.e. /^\**!|@preserve|@license|@cc_on/i) and preserve /@license/i comments.
webpack.config.js
module.exports = {
optimization: {
minimizer: [
new UglifyJsPlugin({
uglifyOptions: {
output: {
comments: /@license/i,
},
},
extractComments: true,
}),
],
},
};
If you avoid building with comments, set uglifyOptions.output.comments to false as in this config:
webpack.config.js
module.exports = {
optimization: {
minimizer: [
new UglifyJsPlugin({
uglifyOptions: {
output: {
comments: false,
},
},
}),
],
},
};
Override default minify function - use terser for minification.
webpack.config.js
module.exports = {
optimization: {
minimizer: [
new UglifyJsPlugin({
// Uncomment lines below for cache invalidation correctly
// cache: true,
// cacheKeys(defaultCacheKeys) {
// delete defaultCacheKeys['uglify-js'];
//
// 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('terser').minify(file, uglifyJsOptions);
},
}),
],
},
};
Please take a moment to read our contributing guidelines if you haven't yet done so.
FAQs
UglifyJS plugin for webpack
The npm package uglifyjs-webpack-plugin receives a total of 525,413 weekly downloads. As such, uglifyjs-webpack-plugin popularity was classified as popular.
We found that uglifyjs-webpack-plugin demonstrated a not healthy version release cadence and project activity because the last version was released a year ago. It has 7 open source maintainers collaborating on the project.
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