[![npm][npm]][npm-url]
[![node][node]][node-url]
[![tests][tests]][tests-url]
[![cover][cover]][cover-url]
[![discussion][discussion]][discussion-url]
[![size][size]][size-url]

terser-webpack-plugin

This plugin uses terser to minify/minimize your JavaScript.

Getting Started

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:

``console
npm install terser-webpack-plugin --save-dev
`

or

`console
yarn add -D terser-webpack-plugin
`

or

`console
pnpm add -D terser-webpack-plugin
`

Then add the plugin to your webpack configuration. For example:

webpack.config.js

`js
const TerserPlugin = require("terser-webpack-plugin");

module.exports = {
optimization: {
minimize: true,
minimizer: [new TerserPlugin()],
},
};
`

Finally, run webpack using the method you normally use (e.g., via CLI or an npm script).

Note about source maps

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 no column information and the minimizer generates only a single line, which leaves only a single mapping.

Using supported devtool values enable source map generation.

Options

- test
- include
- exclude
- parallel
- minify
- terserOptions
- extractComments

$3

Type:

`ts
type test = string | RegExp | (string | RegExp)[];
`

Default: /\.m?js(\?.*)?$/i

Test to match files against.

webpack.config.js

`js
module.exports = {
optimization: {
minimize: true,
minimizer: [
new TerserPlugin({
test: /\.js(\?.*)?$/i,
}),
],
},
};
`

$3

Type:

`ts
type include = string | RegExp | (string | RegExp)[];
`

Default: undefined

Files to include.

webpack.config.js

`js
module.exports = {
optimization: {
minimize: true,
minimizer: [
new TerserPlugin({
include: /\/includes/,
}),
],
},
};
`

$3

Type:

`ts
type exclude = string | RegExp | (string | RegExp)[];
`

Default: undefined

Files to exclude.

webpack.config.js

`js
module.exports = {
optimization: {
minimize: true,
minimizer: [
new TerserPlugin({
exclude: /\/excludes/,
}),
],
},
};
`

$3

Type:

`ts
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 or os.availableParallelism() - 1 (if this function is supported).

> 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 the real available count of CPUs then you need to explicitly set up the number of CPUs to avoid Error: Call retries were exceeded (see #143, #202).

#### boolean

Enable/disable multi-process parallel running.

webpack.config.js

`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

`js
module.exports = {
optimization: {
minimize: true,
minimizer: [
new TerserPlugin({
parallel: 4,
}),
],
},
};
`

$3

Type:

`ts
type minify = (
input: Record,
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 the default minify function.
By default plugin uses terser package.
Useful for using and testing unpublished versions or forks.

> Warning
>
> Always use require inside minify function when parallel option enabled.

webpack.config.js

`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 {
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,
}),
],
},
};
`

$3

Type:

`ts
interface 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

`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,
},
}),
],
},
};
`

$3

Type:

`ts
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 preserve comments that have already been extracted.

#### boolean

Enable/disable extracting comments.

webpack.config.js

`js
module.exports = {
optimization: {
minimize: true,
minimizer: [
new TerserPlugin({
extractComments: true,
}),
],
},
};
`

#### string

Extract all or some (use the /^\**!|@preserve|@license|@cc_on/i RegExp) comments.

webpack.config.js

`js
module.exports = {
optimization: {
minimize: true,
minimizer: [
new TerserPlugin({
extractComments: "all",
}),
],
},
};
`

#### RegExp

All comments that match the given expression will be extracted to a separate file.

webpack.config.js

`js
module.exports = {
optimization: {
minimize: true,
minimizer: [
new TerserPlugin({
extractComments: /@extract/i,
}),
],
},
};
`

#### function

All comments that match the given expression will be extracted to a separate file.

webpack.config.js

`js
module.exports = {
optimization: {
minimize: true,
minimizer: [
new TerserPlugin({
extractComments: (astNode, comment) => {
if (/@extract/i.test(comment.value)) {
return true;
}

return false;
},
}),
],
},
};
`

#### object

Allows you to customize condition for extracting comments, and specify the extracted file name and banner.

webpack.config.js

`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"
${fileData.filename}.LICENSE.txt${fileData.query},
banner: (licenseFile) =>
License information can be found in ${licenseFile},
},
}),
],
},
};
`

##### condition

Type:

`ts
type condition =
| boolean
| "all"
| "some"
| RegExp
| ((
astNode: any,
comment: {
value: string;
type: "comment1" | "comment2" | "comment3" | "comment4";
pos: number;
line: number;
col: number;
},
) => boolean)
| undefined;
`

The condition that determines which comments should be extracted.

webpack.config.js

`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"
${fileData.filename}.LICENSE.txt${fileData.query},
banner: (licenseFile) =>
License information can be found in ${licenseFile},
},
}),
],
},
};
`

##### filename

Type:

`ts
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 .txt extension. Using .js/.cjs/.mjs extensions may conflict with existing assets, which leads to broken code.

webpack.config.js

`js
module.exports = {
optimization: {
minimize: true,
minimizer: [
new TerserPlugin({
extractComments: {
condition: /^\**!|@preserve|@license|@cc_on/i,
filename: "extracted-comments.js",
banner: (licenseFile) =>
License information can be found in ${licenseFile},
},
}),
],
},
};
`

##### banner

Type:

`ts
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 at the top of the original file.

It can be false (no banner), a String, or a function<(string) -> String> that will be called with the filename where the extracted comments have been stored.

The banner will be wrapped in a comment.

webpack.config.js

`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"
${fileData.filename}.LICENSE.txt${fileData.query},
banner: (commentsFile) =>
My custom banner about license information ${commentsFile},
},
}),
],
},
};
`

Examples

$3

Extract all legal comments (i.e. /^\**!|@preserve|@license|@cc_on/i) and preserve /@license/i comments.

webpack.config.js

`js
module.exports = {
optimization: {
minimize: true,
minimizer: [
new TerserPlugin({
terserOptions: {
format: {
comments: /@license/i,
},
},
extractComments: true,
}),
],
},
};
`

$3

If you want to build without comments, use this config:

webpack.config.js

`js
module.exports = {
optimization: {
minimize: true,
minimizer: [
new TerserPlugin({
terserOptions: {
format: {
comments: false,
},
},
extractComments: false,
}),
],
},
};
`

$3

UglifyJS is a JavaScript parser, minifier, compressor and beautifier toolkit.

webpack.config.js

`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: {},
}),
],
},
};
`

$3

swc is a super-fast compiler written in Rust, producing widely supported JavaScript from modern standards and TypeScript.

> Warning
>
> The extractComments option is not supported, and all comments will be removed by default. This will be fixed in future

webpack.config.js

`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: {},
}),
],
},
};
`

$3

esbuild is an extremely fast JavaScript bundler and minifier.

> Warning
>
> The extractComments option is not supported, and all legal comments (i.e. copyright, licenses and etc) will be preserved.

webpack.config.js

`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: {},
}),
],
},
};
`

$3

Override the default minify function - use uglify-js for minification.

webpack.config.js

`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);
},
}),
],
},
};
`

$3

With default Terser minify function:

`ts
module.exports = {
optimization: {
minimize: true,
minimizer: [
new TerserPlugin({
terserOptions: {
compress: true,
},
}),
],
},
};
`

With built-in minify functions:

`ts
import { type JsMinifyOptions as SwcOptions } from "@swc/core";
import { type TransformOptions as EsbuildOptions } from "esbuild";
import { type MinifyOptions as TerserOptions } from "terser";
import { type MinifyOptions as UglifyJSOptions } from "uglify-js";

module.exports = {
optimization: {
minimize: true,
minimizer: [
new TerserPlugin({
minify: TerserPlugin.swcMinify,
terserOptions: {
// swc options
},
}),
new TerserPlugin({
minify: TerserPlugin.uglifyJsMinify,
terserOptions: {
// uglif-js options
},
}),
new TerserPlugin({
minify: TerserPlugin.esbuildMinify,
terserOptions: {
// esbuild options
},
}),

// Alternative usage:
new TerserPlugin({
minify: TerserPlugin.terserMinify,
terserOptions: {
// terser options
},
}),
],
},
};
``

Contributing

We welcome all contributions!
If you're new here, please take a moment to review our contributing guidelines before submitting issues or pull requests.

CONTRIBUTING

License

MIT

[npm]: https://img.shields.io/npm/v/terser-webpack-plugin.svg
[npm-url]: https://npmjs.com/package/terser-webpack-plugin
[node]: https://img.shields.io/node/v/terser-webpack-plugin.svg
[node-url]: https://nodejs.org
[tests]: https://github.com/webpack/terser-webpack-plugin/workflows/terser-webpack-plugin/badge.svg
[tests-url]: https://github.com/webpack/terser-webpack-plugin/actions
[cover]: https://codecov.io/gh/webpack/terser-webpack-plugin/branch/main/graph/badge.svg
[cover-url]: https://codecov.io/gh/webpack/terser-webpack-plugin
[discussion]: https://img.shields.io/github/discussions/webpack/webpack
[discussion-url]: https://github.com/webpack/webpack/discussions
[size]: https://packagephobia.now.sh/badge?p=terser-webpack-plugin
[size-url]: https://packagephobia.now.sh/result?p=terser-webpack-plugin