Security News
New axobject-query Maintainer Faces Backlash Over Controversial Decision to Support Legacy Node.js Versions
A JavaScript library maintainer is under fire after merging a controversial PR to support legacy versions of Node.js.
terser-webpack-plugin
Advanced tools
Package description
The terser-webpack-plugin is a plugin for webpack that uses Terser to minify JavaScript files. It can improve the performance of web applications by reducing the size of the JavaScript bundle, which decreases loading times for users. It also offers options for code compression, mangling, and potentially other optimizations that can be configured to suit various deployment needs.
Minification
This feature allows you to minify your JavaScript files, removing unnecessary whitespace, comments, and code. It helps in reducing the file size and improving load times for your web application.
const TerserPlugin = require('terser-webpack-plugin');
module.exports = {
optimization: {
minimize: true,
minimizer: [new TerserPlugin()],
},
};
Source Map Support
This feature enables the generation of source maps, which help in debugging minified JavaScript by mapping the minified code back to the original source code.
const TerserPlugin = require('terser-webpack-plugin');
module.exports = {
optimization: {
minimize: true,
minimizer: [new TerserPlugin({
sourceMap: true,
})],
},
};
Code Compression
This feature allows for further compression of the JavaScript code, such as removing console logs and other statements that are not needed in production code.
const TerserPlugin = require('terser-webpack-plugin');
module.exports = {
optimization: {
minimize: true,
minimizer: [new TerserPlugin({
terserOptions: {
compress: {
drop_console: true,
},
},
})],
},
};
Mangling
Mangling reduces the size of your code by shortening the names of variables and functions to single characters. This feature is particularly useful for reducing the size of large codebases.
const TerserPlugin = require('terser-webpack-plugin');
module.exports = {
optimization: {
minimize: true,
minimizer: [new TerserPlugin({
terserOptions: {
mangle: true, // Note: `mangle` is `true` by default.
},
})],
},
};
This package is similar to terser-webpack-plugin as it also minifies JavaScript files. However, it uses UglifyJS for minification instead of Terser. Terser is a fork of UglifyJS with ES6+ support, so terser-webpack-plugin might be more suitable for projects using modern JavaScript features.
This plugin uses babel-minify for minifying JavaScript. It is similar to terser-webpack-plugin but leverages the Babel toolchain. It might be a better choice for projects that are already using Babel for JavaScript transpilation.
Closure-webpack-plugin uses Google's Closure Compiler for minifying JavaScript, which is known for its advanced optimizations. It can be more aggressive in optimization compared to terser-webpack-plugin, but it may also require more configuration and might not support all modern JavaScript features as well as Terser.
Readme
This plugin uses terser to minify your JavaScript.
If you are using webpack v5 or above you do not need to install this plugin. Webpack v5 comes with the latest terser-webpack-plugin
out of the box. Using Webpack v4, you have to install terser-webpack-plugin
v4.
To begin, you'll need to install terser-webpack-plugin
:
$ npm install terser-webpack-plugin --save-dev
Then add the plugin to your webpack
config. For example:
webpack.config.js
const TerserPlugin = require("terser-webpack-plugin");
module.exports = {
optimization: {
minimize: true,
minimizer: [new TerserPlugin()],
},
};
And run webpack
via your preferred method.
Works only with source-map
, inline-source-map
, hidden-source-map
and nosources-source-map
values for the devtool
option.
Why?
eval
wraps modules in eval("string")
and the minimizer does not handle strings.cheap
has not column information and minimizer generate only a single line, which leave only a single mapping.Using supported devtool
values enable source map generation.
test
Type: String|RegExp|Array<String|RegExp>
Default: /\.m?js(\?.*)?$/i
Test to match files against.
webpack.config.js
module.exports = {
optimization: {
minimize: true,
minimizer: [
new TerserPlugin({
test: /\.js(\?.*)?$/i,
}),
],
},
};
include
Type: String|RegExp|Array<String|RegExp>
Default: undefined
Files to include.
webpack.config.js
module.exports = {
optimization: {
minimize: true,
minimizer: [
new TerserPlugin({
include: /\/includes/,
}),
],
},
};
exclude
Type: String|RegExp|Array<String|RegExp>
Default: undefined
Files to exclude.
webpack.config.js
module.exports = {
optimization: {
minimize: true,
minimizer: [
new TerserPlugin({
exclude: /\/excludes/,
}),
],
},
};
parallel
Type: Boolean|Number
Default: true
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.
⚠️ If you use Circle CI or any other environment that doesn't provide real available count of CPUs then you need to setup explicitly number of CPUs to avoid
Error: Call retries were exceeded
(see #143, #202).
Boolean
Enable/disable multi-process parallel running.
webpack.config.js
module.exports = {
optimization: {
minimize: true,
minimizer: [
new TerserPlugin({
parallel: true,
}),
],
},
};
Number
Enable multi-process parallel running and set number of concurrent runs.
webpack.config.js
module.exports = {
optimization: {
minimize: true,
minimizer: [
new TerserPlugin({
parallel: 4,
}),
],
},
};
minify
Type: Function
Default: undefined
Allows you to override default minify function. By default plugin uses terser package. Useful for using and testing unpublished versions or forks.
⚠️ Always use
require
insideminify
function whenparallel
option enabled.
webpack.config.js
module.exports = {
optimization: {
minimize: true,
minimizer: [
new TerserPlugin({
terserOptions: {
myCustomOption: true,
},
// Can be async
minify: (file, sourceMap, minimizerOptions) => {
// The `minimizerOptions` option contains option from the `terserOptions` option
// You can use `minimizerOptions.myCustomOption`
const extractedComments = [];
// Custom logic for extract comments
const { map, code } = require("uglify-module") // Or require('./path/to/uglify-module')
.minify(file, {
/* Your options for minification */
});
return { map, code, extractedComments };
},
}),
],
},
};
terserOptions
Type: Object
Default: default
Terser minify options.
webpack.config.js
module.exports = {
optimization: {
minimize: true,
minimizer: [
new TerserPlugin({
terserOptions: {
ecma: undefined,
parse: {},
compress: {},
mangle: true, // Note `mangle.properties` is `false` by default.
module: false,
// Deprecated
output: null,
format: null,
toplevel: false,
nameCache: null,
ie8: false,
keep_classnames: undefined,
keep_fnames: false,
safari10: false,
},
}),
],
},
};
extractComments
Type: Boolean|String|RegExp|Function<(node, comment) -> Boolean|Object>|Object
Default: true
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.txt
.
The terserOptions.format.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.
Boolean
Enable/disable extracting comments.
webpack.config.js
module.exports = {
optimization: {
minimize: true,
minimizer: [
new TerserPlugin({
extractComments: true,
}),
],
},
};
String
Extract all
or some
(use /^\**!|@preserve|@license|@cc_on/i
RegExp) comments.
webpack.config.js
module.exports = {
optimization: {
minimize: true,
minimizer: [
new TerserPlugin({
extractComments: "all",
}),
],
},
};
RegExp
All comments that match the given expression will be extracted to the separate file.
webpack.config.js
module.exports = {
optimization: {
minimize: true,
minimizer: [
new TerserPlugin({
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: {
minimize: true,
minimizer: [
new TerserPlugin({
extractComments: (astNode, comment) => {
if (/@extract/i.test(comment.value)) {
return true;
}
return false;
},
}),
],
},
};
Object
Allow to customize condition for extract comments, specify extracted file name and banner.
webpack.config.js
module.exports = {
optimization: {
minimize: true,
minimizer: [
new TerserPlugin({
extractComments: {
condition: /^\**!|@preserve|@license|@cc_on/i,
filename: (fileData) => {
// The "fileData" argument contains object with "filename", "basename", "query" and "hash"
return `${fileData.filename}.LICENSE.txt${fileData.query}`;
},
banner: (licenseFile) => {
return `License information can be found in ${licenseFile}`;
},
},
}),
],
},
};
condition
Type: Boolean|String|RegExp|Function<(node, comment) -> Boolean|Object>
Condition what comments you need extract.
webpack.config.js
module.exports = {
optimization: {
minimize: true,
minimizer: [
new TerserPlugin({
extractComments: {
condition: "some",
filename: (fileData) => {
// The "fileData" argument contains object with "filename", "basename", "query" and "hash"
return `${fileData.filename}.LICENSE.txt${fileData.query}`;
},
banner: (licenseFile) => {
return `License information can be found in ${licenseFile}`;
},
},
}),
],
},
};
filename
Type: String|Function<(string) -> String>
Default: [file].LICENSE.txt[query]
Available placeholders: [file]
, [query]
and [filebase]
([base]
for webpack 5).
The file where the extracted comments will be stored.
Default is to append the suffix .LICENSE.txt
to the original filename.
⚠️ We highly recommend using the
txt
extension. Usingjs
/cjs
/mjs
extensions may conflict with existing assets which leads to broken code.
webpack.config.js
module.exports = {
optimization: {
minimize: true,
minimizer: [
new TerserPlugin({
extractComments: {
condition: /^\**!|@preserve|@license|@cc_on/i,
filename: "extracted-comments.js",
banner: (licenseFile) => {
return `License information can be found in ${licenseFile}`;
},
},
}),
],
},
};
banner
Type: Boolean|String|Function<(string) -> String>
Default: /*! For license information please see ${commentsFile} */
The banner text that points to the extracted file and will be added on top of the original file.
Can be false
(no banner), a String
, or a Function<(string) -> String>
that will be called with the filename where extracted comments have been stored.
Will be wrapped into comment.
webpack.config.js
module.exports = {
optimization: {
minimize: true,
minimizer: [
new TerserPlugin({
extractComments: {
condition: true,
filename: (fileData) => {
// The "fileData" argument contains object with "filename", "basename", "query" and "hash"
return `${fileData.filename}.LICENSE.txt${fileData.query}`;
},
banner: (commentsFile) => {
return `My custom banner about license information ${commentsFile}`;
},
},
}),
],
},
};
Extract all legal comments (i.e. /^\**!|@preserve|@license|@cc_on/i
) and preserve /@license/i
comments.
webpack.config.js
module.exports = {
optimization: {
minimize: true,
minimizer: [
new TerserPlugin({
terserOptions: {
format: {
comments: /@license/i,
},
},
extractComments: true,
}),
],
},
};
If you avoid building with comments, use this config:
webpack.config.js
module.exports = {
optimization: {
minimize: true,
minimizer: [
new TerserPlugin({
terserOptions: {
format: {
comments: false,
},
},
extractComments: false,
}),
],
},
};
Override default minify function - use uglify-js
for minification.
webpack.config.js
module.exports = {
optimization: {
minimize: true,
minimizer: [
new TerserPlugin({
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);
},
}),
],
},
};
Please take a moment to read our contributing guidelines if you haven't yet done so.
FAQs
Terser plugin for webpack
The npm package terser-webpack-plugin receives a total of 21,032,614 weekly downloads. As such, terser-webpack-plugin popularity was classified as popular.
We found that terser-webpack-plugin demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 3 open source maintainers collaborating on the project.
Did you know?
Socket for GitHub automatically highlights issues in each pull request and monitors the health of all your open source dependencies. Discover the contents of your packages and block harmful activity before you install or update your dependencies.
Security News
A JavaScript library maintainer is under fire after merging a controversial PR to support legacy versions of Node.js.
Security News
Results from the 2023 State of JavaScript Survey highlight key trends, including Vite's dominance, rising TypeScript adoption, and the enduring popularity of React. Discover more insights on developer preferences and technology usage.
Security News
The US Justice Department has penalized two consulting firms $11.3 million for failing to meet cybersecurity requirements on federally funded projects, emphasizing strict enforcement to protect sensitive government data.