terser-webpack-plugin
Advanced tools
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.
This plugin uses terser to minify/minimize your JavaScript.
Webpack v5 comes with the latest terser-webpack-plugin out of the box. If you are using Webpack v5 or above and wish to customize the options, you will still need to install terser-webpack-plugin. 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
or
yarn add -D terser-webpack-plugin
or
pnpm add -D terser-webpack-plugin
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.
testType:
type test = 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,
}),
],
},
};
includeType:
type include = string | RegExp | Array<string | RegExp>;
Default: undefined
Files to include.
webpack.config.js
module.exports = {
optimization: {
minimize: true,
minimizer: [
new TerserPlugin({
include: /\/includes/,
}),
],
},
};
excludeType:
type exclude = string | RegExp | Array<string | RegExp>;
Default: undefined
Files to exclude.
webpack.config.js
module.exports = {
optimization: {
minimize: true,
minimizer: [
new TerserPlugin({
exclude: /\/excludes/,
}),
],
},
};
parallelType:
type parallel = boolean | number;
Default: true
Use multi-process parallel running to improve the build speed.
Default number of concurrent runs: os.cpus().length - 1.
Note
Parallelization can speedup your build significantly and is therefore highly recommended.
Warning
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).
booleanEnable/disable multi-process parallel running.
webpack.config.js
module.exports = {
optimization: {
minimize: true,
minimizer: [
new TerserPlugin({
parallel: true,
}),
],
},
};
numberEnable multi-process parallel running and set number of concurrent runs.
webpack.config.js
module.exports = {
optimization: {
minimize: true,
minimizer: [
new TerserPlugin({
parallel: 4,
}),
],
},
};
minifyType:
type minify = (
input: {
[file: string]: string;
},
sourceMap: import("@jridgewell/trace-mapping").SourceMapInput | undefined,
minifyOptions: {
module?: boolean | undefined;
ecma?: import("terser").ECMA | undefined;
},
extractComments:
| boolean
| "all"
| "some"
| RegExp
| ((
astNode: any,
comment: {
value: string;
type: "comment1" | "comment2" | "comment3" | "comment4";
pos: number;
line: number;
col: number;
}
) => boolean)
| {
condition?:
| boolean
| "all"
| "some"
| RegExp
| ((
astNode: any,
comment: {
value: string;
type: "comment1" | "comment2" | "comment3" | "comment4";
pos: number;
line: number;
col: number;
}
) => boolean)
| undefined;
filename?: string | ((fileData: any) => string) | undefined;
banner?:
| string
| boolean
| ((commentsFile: string) => string)
| undefined;
}
| undefined
) => Promise<{
code: string;
map?: import("@jridgewell/trace-mapping").SourceMapInput | undefined;
errors?: (string | Error)[] | undefined;
warnings?: (string | Error)[] | undefined;
extractedComments?: string[] | undefined;
}>;
Default: TerserPlugin.terserMinify
Allows you to override default minify function. By default plugin uses terser package. Useful for using and testing unpublished versions or forks.
Warning
Always use
requireinsideminifyfunction whenparalleloption enabled.
webpack.config.js
// Can be async
const minify = (input, sourceMap, minimizerOptions, extractsComments) => {
// The `minimizerOptions` option contains option from the `terserOptions` option
// You can use `minimizerOptions.myCustomOption`
// Custom logic for extract comments
const { map, code } = require("uglify-module") // Or require('./path/to/uglify-module')
.minify(input, {
/* Your options for minification */
});
return { map, code, warnings: [], errors: [], extractedComments: [] };
};
// Used to regenerate `fullhash`/`chunkhash` between different implementation
// Example: you fix a bug in custom minimizer/custom function, but unfortunately webpack doesn't know about it, so you will get the same fullhash/chunkhash
// to avoid this you can provide version of your custom minimizer
// You don't need if you use only `contenthash`
minify.getMinimizerVersion = () => {
let packageJson;
try {
// eslint-disable-next-line global-require, import/no-extraneous-dependencies
packageJson = require("uglify-module/package.json");
} catch (error) {
// Ignore
}
return packageJson && packageJson.version;
};
module.exports = {
optimization: {
minimize: true,
minimizer: [
new TerserPlugin({
terserOptions: {
myCustomOption: true,
},
minify,
}),
],
},
};
terserOptionsType:
type terserOptions = {
compress?: boolean | CompressOptions;
ecma?: ECMA;
enclose?: boolean | string;
ie8?: boolean;
keep_classnames?: boolean | RegExp;
keep_fnames?: boolean | RegExp;
mangle?: boolean | MangleOptions;
module?: boolean;
nameCache?: object;
format?: FormatOptions;
/** @deprecated */
output?: FormatOptions;
parse?: ParseOptions;
safari10?: boolean;
sourceMap?: boolean | SourceMapOptions;
toplevel?: boolean;
};
Default: default
Terser 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,
},
}),
],
},
};
extractCommentsType:
type extractComments =
| boolean
| string
| RegExp
| ((
astNode: any,
comment: {
value: string;
type: "comment1" | "comment2" | "comment3" | "comment4";
pos: number;
line: number;
col: number;
}
) => boolean)
| {
condition?:
| boolean
| "all"
| "some"
| RegExp
| ((
astNode: any,
comment: {
value: string;
type: "comment1" | "comment2" | "comment3" | "comment4";
pos: number;
line: number;
col: number;
}
) => boolean)
| undefined;
filename?: string | ((fileData: any) => string) | undefined;
banner?:
| string
| boolean
| ((commentsFile: string) => string)
| undefined;
};
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.
booleanEnable/disable extracting comments.
webpack.config.js
module.exports = {
optimization: {
minimize: true,
minimizer: [
new TerserPlugin({
extractComments: true,
}),
],
},
};
stringExtract all or some (use /^\**!|@preserve|@license|@cc_on/i RegExp) comments.
webpack.config.js
module.exports = {
optimization: {
minimize: true,
minimizer: [
new TerserPlugin({
extractComments: "all",
}),
],
},
};
RegExpAll 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,
}),
],
},
};
functionAll 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;
},
}),
],
},
};
objectAllow 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 ${licenseFile}`;
},
},
}),
],
},
};
conditionType:
type condition =
| boolean
| "all"
| "some"
| RegExp
| ((
astNode: any,
comment: {
value: string;
type: "comment1" | "comment2" | "comment3" | "comment4";
pos: number;
line: number;
col: number;
}
) => boolean)
| undefined;
Condition what comments you need extract.
webpack.config.js
module.exports = {
optimization: {
minimize: true,
minimizer: [
new TerserPlugin({
extractComments: {
condition: "some",
filename: (fileData) => {
// The "fileData" argument contains object with "filename", "basename", "query" and "hash"
return `${fileData.filename}.LICENSE.txt${fileData.query}`;
},
banner: (licenseFile) => {
return `License information can be found in ${licenseFile}`;
},
},
}),
],
},
};
filenameType:
type filename = string | ((fileData: any) => string) | undefined;
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.
Warning
We highly recommend using the
txtextension. Usingjs/cjs/mjsextensions 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}`;
},
},
}),
],
},
};
bannerType:
type banner = string | boolean | ((commentsFile: string) => string) | undefined;
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,
}),
],
},
};
uglify-jsUglifyJS is a JavaScript parser, minifier, compressor and beautifier toolkit.
webpack.config.js
module.exports = {
optimization: {
minimize: true,
minimizer: [
new TerserPlugin({
minify: TerserPlugin.uglifyJsMinify,
// `terserOptions` options will be passed to `uglify-js`
// Link to options - https://github.com/mishoo/UglifyJS#minify-options
terserOptions: {},
}),
],
},
};
swcswc is a super-fast compiler written in rust; producing widely-supported javascript from modern standards and typescript.
Warning
the
extractCommentsoption is not supported and all comments will be removed by default, it will be fixed in future
webpack.config.js
module.exports = {
optimization: {
minimize: true,
minimizer: [
new TerserPlugin({
minify: TerserPlugin.swcMinify,
// `terserOptions` options will be passed to `swc` (`@swc/core`)
// Link to options - https://swc.rs/docs/config-js-minify
terserOptions: {},
}),
],
},
};
esbuildesbuild is an extremely fast JavaScript bundler and minifier.
Warning
the
extractCommentsoption is not supported and all legal comments (i.e. copyright, licenses and etc) will be preserved
webpack.config.js
module.exports = {
optimization: {
minimize: true,
minimizer: [
new TerserPlugin({
minify: TerserPlugin.esbuildMinify,
// `terserOptions` options will be passed to `esbuild`
// Link to options - https://esbuild.github.io/api/#minify
// Note: the `minify` options is true by default (and override other `minify*` options), so if you want to disable the `minifyIdentifiers` option (or other `minify*` options) please use:
// terserOptions: {
// minify: false,
// minifyWhitespace: true,
// minifyIdentifiers: false,
// minifySyntax: true,
// },
terserOptions: {},
}),
],
},
};
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);
},
}),
],
},
};
With default terser minify function:
module.exports = {
optimization: {
minimize: true,
minimizer: [
new TerserPlugin({
terserOptions: {
compress: true,
},
}),
],
},
};
With built-in minify functions:
import type { JsMinifyOptions as SwcOptions } from "@swc/core";
import type { MinifyOptions as UglifyJSOptions } from "uglify-js";
import type { TransformOptions as EsbuildOptions } from "esbuild";
import type { MinifyOptions as TerserOptions } from "terser";
module.exports = {
optimization: {
minimize: true,
minimizer: [
new TerserPlugin<SwcOptions>({
minify: TerserPlugin.swcMinify,
terserOptions: {
// `swc` options
},
}),
new TerserPlugin<UglifyJSOptions>({
minify: TerserPlugin.uglifyJsMinify,
terserOptions: {
// `uglif-js` options
},
}),
new TerserPlugin<EsbuildOptions>({
minify: TerserPlugin.esbuildMinify,
terserOptions: {
// `esbuild` options
},
}),
// Alternative usage:
new TerserPlugin<TerserOptions>({
minify: TerserPlugin.terserMinify,
terserOptions: {
// `terser` options
},
}),
],
},
};
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 15,561,392 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.
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