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# terser-webpack-plugin
This plugin uses [terser](https://github.com/terser-js/terser) to minify your JavaScript.
> ℹ️ For `webpack@3` use [terser-webpack-plugin-legacy](https://www.npmjs.com/package/terser-webpack-plugin-legacy) package
## Getting Started
To begin, you'll need to install `terser-webpack-plugin`:
```console
$ npm install terser-webpack-plugin --save-dev
```
Then add the plugin to your `webpack` config. For example:
**webpack.config.js**
```js
const TerserPlugin = require('terser-webpack-plugin');
module.exports = {
optimization: {
minimizer: [new TerserPlugin()],
},
};
```
And run `webpack` via your preferred method.
## Options
### `test`
Type: `String|RegExp|Array<String|RegExp>`
Default: `/\.m?js(\?.*)?$/i`
Test to match files against.
**webpack.config.js**
```js
module.exports = {
optimization: {
minimizer: [
new TerserPlugin({
test: /\.js(\?.*)?$/i,
}),
],
},
};
```
### `include`
Type: `String|RegExp|Array<String|RegExp>`
Default: `undefined`
Files to include.
**webpack.config.js**
```js
module.exports = {
optimization: {
minimizer: [
new TerserPlugin({
include: /\/includes/,
}),
],
},
};
```
### `exclude`
Type: `String|RegExp|Array<String|RegExp>`
Default: `undefined`
Files to exclude.
**webpack.config.js**
```js
module.exports = {
optimization: {
minimizer: [
new TerserPlugin({
exclude: /\/excludes/,
}),
],
},
};
```
### `chunkFilter`
Type: `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**
```js
module.exports = {
optimization: {
minimizer: [
new TerserPlugin({
chunkFilter: (chunk) => {
// Exclude uglification for the `vendor` chunk
if (chunk.name === 'vendor') {
return false;
}
return true;
},
}),
],
},
};
```
### `cache`
Type: `Boolean|String`
Default: `false`
Enable file caching.
Default path to cache directory: `node_modules/.cache/terser-webpack-plugin`.
> ℹ️ If you use your own `minify` function please read the `minify` section for cache invalidation correctly.
#### `Boolean`
Enable/disable file caching.
**webpack.config.js**
```js
module.exports = {
optimization: {
minimizer: [
new TerserPlugin({
cache: true,
}),
],
},
};
```
#### `String`
Enable file caching and set path to cache directory.
**webpack.config.js**
```js
module.exports = {
optimization: {
minimizer: [
new TerserPlugin({
cache: 'path/to/cache',
}),
],
},
};
```
### `cacheKeys`
Type: `Function<(defaultCacheKeys, file) -> Object>`
Default: `defaultCacheKeys => defaultCacheKeys`
Allows you to override default cache keys.
Default cache keys:
```js
({
terser: require('terser/package.json').version, // terser version
'terser-webpack-plugin': require('../package.json').version, // plugin version
'terser-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**
```js
module.exports = {
optimization: {
minimizer: [
new TerserPlugin({
cache: true,
cacheKeys: (defaultCacheKeys, file) => {
defaultCacheKeys.myCacheKey = 'myCacheKeyValue';
return defaultCacheKeys;
},
}),
],
},
};
```
### `parallel`
Type: `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**.
#### `Boolean`
Enable/disable multi-process parallel running.
**webpack.config.js**
```js
module.exports = {
optimization: {
minimizer: [
new TerserPlugin({
parallel: true,
}),
],
},
};
```
#### `Number`
Enable multi-process parallel running and set number of concurrent runs.
**webpack.config.js**
```js
module.exports = {
optimization: {
minimizer: [
new TerserPlugin({
parallel: 4,
}),
],
},
};
```
### `sourceMap`
Type: `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-map` options don't work with this plugin**.
**webpack.config.js**
```js
module.exports = {
optimization: {
minimizer: [
new TerserPlugin({
sourceMap: true,
}),
],
},
};
```
### `minify`
Type: `Function`
Default: `undefined`
Allows you to override default minify function.
By default plugin uses [terser](https://github.com/terser-js/terser) package.
Useful for using and testing unpublished versions or forks.
> ⚠️ **Always use `require` inside `minify` function when `parallel` option enabled**.
**webpack.config.js**
```js
module.exports = {
optimization: {
minimizer: [
new TerserPlugin({
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 };
},
}),
],
},
};
```
### `terserOptions`
Type: `Object`
Default: [default](https://github.com/terser-js/terser#minify-options)
Terser minify [options](https://github.com/terser-js/terser#minify-options).
**webpack.config.js**
```js
module.exports = {
optimization: {
minimizer: [
new TerserPlugin({
terserOptions: {
ecma: undefined,
warnings: false,
parse: {},
compress: {},
mangle: true, // Note `mangle.properties` is `false` by default.
module: false,
output: 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: `false`
Whether comments shall be extracted to a separate file, (see [details](https://github.com/webpack/webpack/commit/71933e979e51c533b432658d5e37917f9e71595a)).
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 `terserOptions.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.
#### `Boolean`
Enable/disable extracting comments.
**webpack.config.js**
```js
module.exports = {
optimization: {
minimizer: [
new TerserPlugin({
extractComments: true,
}),
],
},
};
```
#### `String`
Extract `all` or `some` (use `/^\**!|@preserve|@license|@cc_on/i` RegExp) comments.
**webpack.config.js**
```js
module.exports = {
optimization: {
minimizer: [
new TerserPlugin({
extractComments: 'all',
}),
],
},
};
```
#### `RegExp`
All comments that match the given expression will be extracted to the separate file.
**webpack.config.js**
```js
module.exports = {
optimization: {
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**
```js
module.exports = {
optimization: {
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**
```js
module.exports = {
optimization: {
minimizer: [
new TerserPlugin({
extractComments: {
condition: /^\**!|@preserve|@license|@cc_on/i,
filename: (file) => {
return `${file}.LICENSE`;
},
banner: (licenseFile) => {
return `License information can be found in ${licenseFile}`;
},
},
}),
],
},
};
```
##### `condition`
Type: `Boolean|String|RegExp|Function<(node, comment) -> Boolean|Object>`
Condition what comments you need extract.
**webpack.config.js**
```js
module.exports = {
optimization: {
minimizer: [
new TerserPlugin({
extractComments: {
condition: 'some',
filename: (file) => {
return `${file}.LICENSE`;
},
banner: (licenseFile) => {
return `License information can be found in ${licenseFile}`;
},
},
}),
],
},
};
```
##### `filename`
Type: `String|Function<(string) -> String>`
Default: `${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**
```js
module.exports = {
optimization: {
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 ${commentsFile} */`
The banner text that points to the extracted file and will be added on top of the original file.
Can be `false` (no banner), a `String`, or a `Function<(string) -> String>` that will be called with the filename where extracted comments have been stored.
Will be wrapped into comment.
**webpack.config.js**
```js
module.exports = {
optimization: {
minimizer: [
new TerserPlugin({
extractComments: {
condition: true,
filename: (file) => {
return `${file}.LICENSE`;
},
banner: (commentsFile) => {
return `My custom banner about license information ${commentsFile}`;
},
},
}),
],
},
};
```
### `warningsFilter`
Type: `Function<(warning, source) -> Boolean>`
Default: `() => true`
Allow to filter [terser](https://github.com/terser-js/terser) warnings.
Return `true` to keep the warning, `false` otherwise.
**webpack.config.js**
```js
module.exports = {
optimization: {
minimizer: [
new TerserPlugin({
warningsFilter: (warning, source) => {
if (/Dropping unreachable code/i.test(warning)) {
return true;
}
if (/filename\.js/i.test(source)) {
return true;
}
return false;
},
}),
],
},
};
```
## Examples
### Cache And Parallel
Enable cache and multi-process parallel running.
**webpack.config.js**
```js
module.exports = {
optimization: {
minimizer: [
new TerserPlugin({
cache: true,
parallel: true,
}),
],
},
};
```
### Preserve Comments
Extract all legal comments (i.e. `/^\**!|@preserve|@license|@cc_on/i`) and preserve `/@license/i` comments.
**webpack.config.js**
```js
module.exports = {
optimization: {
minimizer: [
new TerserPlugin({
terserOptions: {
output: {
comments: /@license/i,
},
},
extractComments: true,
}),
],
},
};
```
### Remove Comments
If you avoid building with comments, set **terserOptions.output.comments** to **false** as in this config:
**webpack.config.js**
```js
module.exports = {
optimization: {
minimizer: [
new TerserPlugin({
terserOptions: {
output: {
comments: false,
},
},
}),
],
},
};
```
### Custom Minify Function
Override default minify function - use `uglify-js` for minification.
**webpack.config.js**
```js
module.exports = {
optimization: {
minimizer: [
new TerserPlugin({
// Uncomment lines below for cache invalidation correctly
// cache: true,
// cacheKeys: (defaultCacheKeys) => {
// delete defaultCacheKeys.terser;
//
// 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);
},
}),
],
},
};
```
## Contributing
Please take a moment to read our contributing guidelines if you haven't yet done so.
[CONTRIBUTING](./.github/CONTRIBUTING.md)
## License
[MIT](./LICENSE)
[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
[deps]: https://david-dm.org/webpack-contrib/terser-webpack-plugin.svg
[deps-url]: https://david-dm.org/webpack-contrib/terser-webpack-plugin
[tests]: https://dev.azure.com/webpack-contrib/terser-webpack-plugin/_apis/build/status/webpack-contrib.terser-webpack-plugin?branchName=master
[tests-url]: https://dev.azure.com/webpack-contrib/terser-webpack-plugin/_build/latest?definitionId=7&branchName=master
[cover]: https://codecov.io/gh/webpack-contrib/terser-webpack-plugin/branch/master/graph/badge.svg
[cover-url]: https://codecov.io/gh/webpack-contrib/terser-webpack-plugin
[chat]: https://img.shields.io/badge/gitter-webpack%2Fwebpack-brightgreen.svg
[chat-url]: https://gitter.im/webpack/webpack
[size]: https://packagephobia.now.sh/badge?p=terser-webpack-plugin
[size-url]: https://packagephobia.now.sh/result?p=terser-webpack-plugin
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