node_modules/uglifyjs-webpack-plugin/README.md

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<div align="center">
  <a href="https://github.com/webpack/webpack">
    <img width="200" height="200"
      src="https://cdn.rawgit.com/webpack/media/e7485eb2/logo/icon.svg">
  </a>
  <h1>UglifyJS Webpack Plugin</h1>
	<p>This plugin uses <a href="https://github.com/mishoo/UglifyJS2/tree/harmony">UglifyJS v3 </a><a href="https://npmjs.com/package/uglify-es">(`uglify-es`)</a> to minify your JavaScript</p>
</div>
> ℹ️  `webpack < v4.0.0` currently contains [`v0.4.6`](https://github.com/webpack-contrib/uglifyjs-webpack-plugin/tree/version-0.4) of this plugin under `webpack.optimize.UglifyJsPlugin` as an alias. For usage of the latest version (`v1.0.0`), please follow the instructions below. Aliasing `v1.0.0` as `webpack.optimize.UglifyJsPlugin` is scheduled for `webpack v4.0.0`
<h2 align="center">Install</h2>
```bash
npm i -D uglifyjs-webpack-plugin
```
<h2 align="center">Usage</h2>
**webpack.config.js**
```js
const UglifyJsPlugin = require('uglifyjs-webpack-plugin')
module.exports = {
  //...
  optimization: {
    minimizer: [
      new UglifyJsPlugin()
    ]
  }
}
```
<h2 align="center">Options</h2>
|Name|Type|Default|Description|
|:--:|:--:|:-----:|:----------|
|**`test`**|`{RegExp\|Array<RegExp>}`| <code>/\\.js$/i</code>|Test to match files against|
|**`include`**|`{RegExp\|Array<RegExp>}`|`undefined`|Files to `include`|
|**`exclude`**|`{RegExp\|Array<RegExp>}`|`undefined`|Files to `exclude`|
|**`cache`**|`{Boolean\|String}`|`false`|Enable file caching|
|**`cacheKeys`**|`{Function(defaultCacheKeys, file) -> {Object}}`|`defaultCacheKeys => defaultCacheKeys`|Allows you to override default cache keys|
|**`parallel`**|`{Boolean\|Number}`|`false`|Use multi-process parallel running to improve the build speed|
|**`sourceMap`**|`{Boolean}`|`false`|Use source maps to map error message locations to modules (This slows down the compilation) ⚠️ **`cheap-source-map` options don't work with this plugin**|
|**`minify`**|`{Function}`|`undefined`|Allows you to override default minify function|
|**`uglifyOptions`**|`{Object}`|[`{...defaults}`](https://github.com/webpack-contrib/uglifyjs-webpack-plugin/tree/master#uglifyoptions)|`uglify` [Options](https://github.com/mishoo/UglifyJS2/tree/harmony#minify-options)|
|**`extractComments`**|`{Boolean\|RegExp\|Function<(node, comment) -> {Boolean\|Object}>}`|`false`|Whether comments shall be extracted to a separate file, (see [details](https://github.com/webpack/webpack/commit/71933e979e51c533b432658d5e37917f9e71595a) (`webpack >= 2.3.0`)|
|**`warningsFilter`**|`{Function(source) -> {Boolean}}`|`() => true`|Allow to filter uglify warnings|
### `test`
**webpack.config.js**
```js
[
  new UglifyJsPlugin({
    test: /\.js($|\?)/i
  })
]
```
### `include`
**webpack.config.js**
```js
[
  new UglifyJsPlugin({
    include: /\/includes/
  })
]
```
### `exclude`
**webpack.config.js**
```js
[
  new UglifyJsPlugin({
    exclude: /\/excludes/
  })
]
```
### `cache`
If you use your own `minify` function please read the `minify` section for cache invalidation correctly.
#### `{Boolean}`
**webpack.config.js**
```js
[
  new UglifyJsPlugin({
    cache: true
  })
]
```
Enable file caching.
Default path to cache directory: `node_modules/.cache/uglifyjs-webpack-plugin`.
#### `{String}`
**webpack.config.js**
```js
[
  new UglifyJsPlugin({
    cache: 'path/to/cache'
  })
]
```
Path to cache directory.
### `cacheKeys`
**webpack.config.js**
```js
[
  new UglifyJsPlugin({
    cache: true,
    cacheKeys: (defaultCacheKeys, file) => {
      defaultCacheKeys.myCacheKey = 'myCacheKeyValue';
      
      return defaultCacheKeys;
    },
  })
]
```
Allows you to override default cache keys.
Default keys:
```js
{
  'uglify-es': versions.uglify, // uglify version
  'uglifyjs-webpack-plugin': versions.plugin, // plugin version
  'uglifyjs-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
}
```
### `parallel`
#### `{Boolean}`
**webpack.config.js**
```js
[
  new UglifyJsPlugin({
    parallel: true
  })
]
```
Enable parallelization.
Default number of concurrent runs: `os.cpus().length - 1`.
#### `{Number}`
**webpack.config.js**
```js
[
  new UglifyJsPlugin({
    parallel: 4
  })
]
```
Number of concurrent runs.
> ℹ️  Parallelization can speedup your build significantly and is therefore **highly recommended**
### `sourceMap`
If you use your own `minify` function please read the `minify` section for handling source maps correctly.
**webpack.config.js**
```js
[
  new UglifyJsPlugin({
    sourceMap: true
  })
]
```
> ⚠️ **`cheap-source-map` options don't work with this plugin**
### `minify`
> ⚠️ **Always use `require` inside `minify` function when `parallel` option enabled**
**webpack.config.js**
```js
[
  new UglifyJsPlugin({
     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 };
      }
  })
]
```
By default plugin uses `uglify-es` package.
Examples:
#### `uglify-js`
```bash
npm i -D uglify-js
```
**webpack.config.js**
```js
[
  new UglifyJsPlugin({
    // Uncomment lines below for cache invalidation correctly
    // cache: true,
    // cacheKeys(defaultCacheKeys) {
    //   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);
    }
  })
]
```
#### `terser`
```bash
npm i -D terser
```
**webpack.config.js**
```js
[
  new UglifyJsPlugin({
    // Uncomment lines below for cache invalidation correctly
    // cache: true,
    // cacheKeys(defaultCacheKeys) {
    //   return Object.assign(
    //     {},
    //     defaultCacheKeys,
    //     { terser: require('terser/package.json').version },
    //   );
    // },
    minify(file, sourceMap) {
      // https://github.com/fabiosantoscode/terser#minify-options
      const terserOptions = { /* your `terser` package options */ };
      if (sourceMap) {
        terserOption.sourceMap = {
          content: sourceMap,
        };
      }
      return require('terser').minify(file, terserOptions);
    }
  })
]
```
### [`uglifyOptions`](https://github.com/mishoo/UglifyJS2/tree/harmony#minify-options)
|Name|Type|Default|Description|
|:--:|:--:|:-----:|:----------|
|**`ecma`**|`{Number}`|`undefined`|Supported ECMAScript Version (`5`, `6`, `7` or `8`). Affects `parse`, `compress` && `output` options|
|**`warnings`**|`{Boolean}`|`false`|Display Warnings|
|**[`parse`](https://github.com/mishoo/UglifyJS2/tree/harmony#parse-options)**|`{Object}`|`{}`|Additional Parse Options|
|**[`compress`](https://github.com/mishoo/UglifyJS2/tree/harmony#compress-options)**|`{Boolean\|Object}`|`true`|Additional Compress Options|
|**[`mangle`](https://github.com/mishoo/UglifyJS2/tree/harmony#mangle-options)**|`{Boolean\|Object}`|`{inline: false}`|Enable Name Mangling (See [Mangle Properties](https://github.com/mishoo/UglifyJS2/tree/harmony#mangle-properties-options) for advanced setups, use with ⚠️)|
|**[`output`](https://github.com/mishoo/UglifyJS2/tree/harmony#output-options)**|`{Object}`|`{comments: extractComments ? false : /^\**!\|@preserve\|@license\|@cc_on/,}`|Additional Output Options (The defaults are optimized for best compression)|
|**`toplevel`**|`{Boolean}`|`false`|Enable top level variable and function name mangling and to drop unused variables and functions|
|**`nameCache`**|`{Object}`|`null`|Enable cache of mangled variable and property names across multiple invocations|
|**`ie8`**|`{Boolean}`|`false`|Enable IE8 Support|
|**`keep_classnames`**|`{Boolean}`|`undefined`|Enable prevent discarding or mangling of class names|
|**`keep_fnames`**|`{Boolean}`|`false`| Enable prevent discarding or mangling of function names. Useful for code relying on `Function.prototype.name`. If the top level minify option `keep_classnames` is `undefined` it will be overriden with the value of the top level minify option `keep_fnames`|
|**`safari10`**|`{Boolean}`|`false`|Enable work around Safari 10/11 bugs in loop scoping and `await`|
**webpack.config.js**
```js
[
  new UglifyJsPlugin({
    uglifyOptions: {
      ecma: 8,
      warnings: false,
      parse: {...options},
      compress: {...options},
      mangle: {
        ...options,
        properties: {
          // mangle property options
        }
      },
      output: {
        comments: false,
        beautify: false,
        ...options
      },
      toplevel: false,
      nameCache: null,
      ie8: false,
      keep_classnames: undefined,
      keep_fnames: false,
      safari10: false,
    }
  })
]
```
### `extractComments`
#### `{Boolean}`
All comments that normally would be preserved by the `comments` option will be moved to a separate file. If the original file is named `foo.js`, then the comments will be stored to `foo.js.LICENSE`.
#### `{RegExp|String}` or  `{Function<(node, comment) -> {Boolean}>}`
All comments that match the given expression (resp. are evaluated to `true` by the function) will be extracted to the separate file. The `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.
#### `{Object}`
|Name|Type|Default|Description|
|:--:|:--:|:-----:|:----------|
|**`condition`**|`{Regex\|Function}`|``|Regular Expression or function (see previous point)|
|**`filename`**|`{String\|Function}`|`${file}.LICENSE`|The file where the extracted comments will be stored. Can be either a `{String}` or a `{Function<(string) -> {String}>}`, which will be given the original filename. Default is to append the suffix `.LICENSE` to the original filename|
|**`banner`**|`{Boolean\|String\|Function}`|`/*! For license information please see ${filename}.js.LICENSE */`|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|
### `warningsFilter`
**webpack.config.js**
```js
[
  new UglifyJsPlugin({
    warningsFilter: (src) => true
  })
]
```
<h2 align="center">Maintainers</h2>
<table>
  <tbody>
    <tr>
      <td align="center">
        <a href="https://github.com/hulkish">
          <img width="150" height="150" src="https://github.com/hulkish.png?size=150">
          </br>
          Steven Hargrove
        </a>
      </td>
      <td align="center">
        <a href="https://github.com/bebraw">
          <img width="150" height="150" src="https://github.com/bebraw.png?v=3&s=150">
          </br>
          Juho Vepsäläinen
        </a>
      </td>
      <td align="center">
        <a href="https://github.com/d3viant0ne">
          <img width="150" height="150" src="https://github.com/d3viant0ne.png?v=3&s=150">
          </br>
          Joshua Wiens
        </a>
      </td>
      <td align="center">
        <a href="https://github.com/michael-ciniawsky">
          <img width="150" height="150" src="https://github.com/michael-ciniawsky.png?v=3&s=150">
          </br>
          Michael Ciniawsky
        </a>
      </td>
      <td align="center">
        <a href="https://github.com/evilebottnawi">
          <img width="150" height="150" src="https://github.com/evilebottnawi.png?v=3&s=150">
          </br>
          Alexander Krasnoyarov
        </a>
      </td>
    </tr>
  <tbody>
</table>
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