path: root/node_modules/mini-css-extract-plugin/README.md

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  <h1>mini-css-extract-plugin</h1>
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[![npm][npm]][npm-url]
[![deps][deps]][deps-url]
[![tests][tests]][tests-url]
[![coverage][cover]][cover-url]
[![chat][chat]][chat-url]

This plugin extracts CSS into separate files. It creates a CSS file per JS file which contains CSS. It supports On-Demand-Loading of CSS and SourceMaps.

It builds on top of a new webpack v4 feature (module types) and requires webpack 4 to work.

Compared to the extract-text-webpack-plugin:

* Async loading
* No duplicate compilation (performance)
* Easier to use
* Specific to CSS

TODO:

* HMR support

<h2 align="center">Install</h2>

```bash
npm install --save-dev mini-css-extract-plugin
```

<h2 align="center">Usage</h2>

### Configuration

#### Minimal example

**webpack.config.js**

```js
const MiniCssExtractPlugin = require("mini-css-extract-plugin");
module.exports = {
  plugins: [
    new MiniCssExtractPlugin({
      // Options similar to the same options in webpackOptions.output
      // both options are optional
      filename: "[name].css",
      chunkFilename: "[id].css"
    })
  ],
  module: {
    rules: [
      {
        test: /\.css$/,
        use: [
          {
            loader: MiniCssExtractPlugin.loader,
            options: {
              // you can specify a publicPath here
              // by default it use publicPath in webpackOptions.output
              publicPath: '../'
            }
          },
          "css-loader"
        ]
      }
    ]
  }
}
```

#### Advanced configuration example

This plugin should be used only on `production` builds without `style-loader` in the loaders chain, especially if you want to have HMR in `development`.

Here is an example to have both HMR in `development` and your styles extracted in a file for `production` builds.

(Loaders options left out for clarity, adapt accordingly to your needs.)


**webpack.config.js**

```js
const MiniCssExtractPlugin = require("mini-css-extract-plugin");
const devMode = process.env.NODE_ENV !== 'production'

module.exports = {
  plugins: [
    new MiniCssExtractPlugin({
      // Options similar to the same options in webpackOptions.output
      // both options are optional
      filename: devMode ? '[name].css' : '[name].[hash].css',
      chunkFilename: devMode ? '[id].css' : '[id].[hash].css',
    })
  ],
  module: {
    rules: [
      {
        test: /\.(sa|sc|c)ss$/,
        use: [
          devMode ? 'style-loader' : MiniCssExtractPlugin.loader,
          'css-loader',
          'postcss-loader',
          'sass-loader',
        ],
      }
    ]
  }
}
```

### Minimizing For Production

While webpack 5 is likely to come with a CSS minimizer built-in, with webpack 4 you need to bring your own. To minify the output, use a plugin like [optimize-css-assets-webpack-plugin](https://github.com/NMFR/optimize-css-assets-webpack-plugin). Setting `optimization.minimizer` overrides the defaults provided by webpack, so make sure to also specify a JS minimizer:

**webpack.config.js**

```js
const UglifyJsPlugin = require("uglifyjs-webpack-plugin");
const MiniCssExtractPlugin = require("mini-css-extract-plugin");
const OptimizeCSSAssetsPlugin = require("optimize-css-assets-webpack-plugin");
module.exports = {
  optimization: {
    minimizer: [
      new UglifyJsPlugin({
        cache: true,
        parallel: true,
        sourceMap: true // set to true if you want JS source maps
      }),
      new OptimizeCSSAssetsPlugin({})
    ]
  },
  plugins: [
    new MiniCssExtractPlugin({
      filename: "[name].css",
      chunkFilename: "[id].css"
    })
  ],
  module: {
    rules: [
      {
        test: /\.css$/,
        use: [
          MiniCssExtractPlugin.loader,
          "css-loader"
        ]
      }
    ]
  }
}
```

### Features

#### Using preloaded or inlined CSS

The runtime code detects already added CSS via `<link>` or `<style>` tag.
This can be useful when injecting CSS on server-side for Server-Side-Rendering.
The `href` of the `<link>` tag has to match the URL that will be used for loading the CSS chunk.
The `data-href` attribute can be used for `<link>` and `<style>` too.
When inlining CSS `data-href` must be used.

#### Extracting all CSS in a single file

Similar to what [extract-text-webpack-plugin](https://github.com/webpack-contrib/extract-text-webpack-plugin) does, the CSS
can be extracted in one CSS file using `optimization.splitChunks.cacheGroups`.

**webpack.config.js**

```js
const MiniCssExtractPlugin = require("mini-css-extract-plugin");
module.exports = {
  optimization: {
    splitChunks: {
      cacheGroups: {
        styles: {
          name: 'styles',
          test: /\.css$/,
          chunks: 'all',
          enforce: true
        }
      }
    }
  },
  plugins: [
    new MiniCssExtractPlugin({
      filename: "[name].css",
    })
  ],
  module: {
    rules: [
      {
        test: /\.css$/,
        use: [
          MiniCssExtractPlugin.loader,
          "css-loader"
        ]
      }
    ]
  }
}
```

#### Extracting CSS based on entry

You may also extract the CSS based on the webpack entry name. This is especially useful if you import routes dynamically
but want to keep your CSS bundled according to entry. This also prevents the CSS duplication issue one had with the
ExtractTextPlugin.

```javascript
const path = require('path');
const MiniCssExtractPlugin = require("mini-css-extract-plugin");

function recursiveIssuer(m) {
  if (m.issuer) {
    return recursiveIssuer(m.issuer);
  } else if (m.name) {
    return m.name;
  } else {
    return false;
  }
}

module.exports = {
  entry: {
    foo: path.resolve(__dirname, 'src/foo'),
    bar: path.resolve(__dirname, 'src/bar')
  },
  optimization: {
    splitChunks: {
      cacheGroups: {
        fooStyles: {
          name: 'foo',
          test: (m,c,entry = 'foo') => m.constructor.name === 'CssModule' && recursiveIssuer(m) === entry,
          chunks: 'all',
          enforce: true
        },
        barStyles: {
          name: 'bar',
          test: (m,c,entry = 'bar') => m.constructor.name === 'CssModule' && recursiveIssuer(m) === entry,
          chunks: 'all',
          enforce: true
        }
      }
    }
  },
  plugins: [
    new MiniCssExtractPlugin({
      filename: "[name].css",
    })
  ],
  module: {
    rules: [
      {
        test: /\.css$/,
        use: [
          MiniCssExtractPlugin.loader,
          "css-loader"
        ]
      }
    ]
  }
}
```

#### Long Term Caching

For long term caching use `filename: "[contenthash].css"`. Optionally add `[name]`.

### Media Query Plugin

If you'd like to extract the media queries from the extracted CSS (so mobile users don't need to load desktop or tablet specific CSS anymore) you should use one of the following plugins:

- [Media Query Plugin](https://github.com/SassNinja/media-query-plugin)
- [Media Query Splitting Plugin](https://github.com/mike-diamond/media-query-splitting-plugin)


<h2 align="center">Maintainers</h2>

<table>
  <tbody>
    <tr>
      <td align="center">
        <a href="https://github.com/sokra">
          <img width="150" height="150" src="https://github.com/sokra.png?size=150">
          </br>
          Tobias Koppers
        </a>
      </td>
    </tr>
  <tbody>
</table>


## License

#### [MIT](./LICENSE)

[npm]: https://img.shields.io/npm/v/mini-css-extract-plugin.svg
[npm-url]: https://npmjs.com/package/mini-css-extract-plugin

[node]: https://img.shields.io/node/v/mini-css-extract-plugin.svg
[node-url]: https://nodejs.org

[deps]: https://david-dm.org/webpack-contrib/mini-css-extract-plugin.svg
[deps-url]: https://david-dm.org/webpack-contrib/mini-css-extract-plugin

[tests]: 	https://img.shields.io/circleci/project/github/webpack-contrib/mini-css-extract-plugin.svg
[tests-url]: https://circleci.com/gh/webpack-contrib/mini-css-extract-plugin

[cover]: https://codecov.io/gh/webpack-contrib/mini-css-extract-plugin/branch/master/graph/badge.svg
[cover-url]: https://codecov.io/gh/webpack-contrib/mini-css-extract-plugin

[chat]: https://img.shields.io/badge/gitter-webpack%2Fwebpack-brightgreen.svg
[chat-url]: https://gitter.im/webpack/webpack