**Works only with `source-map`, `inline-source-map`, `hidden-source-map` and `nosources-source-map` values for the [`devtool`](https://webpack.js.org/configuration/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.
## Options
### `test`
Type: `String|RegExp|Array<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,
}),
],
},
};
```
### `include`
Type: `String|RegExp|Array<String|RegExp>`
Default: `undefined`
Files to include.
**webpack.config.js**
```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**
```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](https://github.com/webpack-contrib/terser-webpack-plugin/issues/143), [#202](https://github.com/webpack-contrib/terser-webpack-plugin/issues/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,
}),
],
},
};
```
### `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Useful for using and testing unpublished versions or forks.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: {
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')
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.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**
```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**
```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**
```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**
```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**
```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"
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: {
minimize: true,
minimizer: [
new TerserPlugin({
extractComments: {
condition: true,
filename: (fileData) => {
// The "fileData" argument contains object with "filename", "basename", "query" and "hash"