extract-jss-webpack-plugin v2.1.2

# for webpack 2
npm install --save-dev extract-jss-webpack-plugin
# for webpack 1
npm install --save-dev extract-jss-webpack-plugin@1.0.1

:warning: For webpack v1, see the README in the webpack-1 branch.

const ExtractJssPlugin = require("extract-jss-webpack-plugin");

module.exports = {
  module: {
    rules: [
      {
        test: /\.css$/,
        use: ExtractJssPlugin.extract({
          fallback: "style-loader",
          use: "css-loader"
        })
      }
    ]
  },
  plugins: [
    new ExtractJssPlugin("styles.css"),
  ]
}

It moves all the required *.css modules in entry chunks into a separate CSS file. So your styles are no longer inlined into the JS bundle, but in a separate CSS file (styles.css). If your total stylesheet volume is big, it will be faster because the CSS bundle is loaded in parallel to the JS bundle.

new ExtractJssPlugin(options: filename | object)

• [name] name of the chunk
• [id] number of the chunk
• [contenthash] hash of the content of the extracted file

:warning: ExtractJssPlugin generates a file per entry, so you must use [name], [id] or [contenthash] when using multiple entries.

#extract

ExtractJssPlugin.extract(options: loader | object)

Creates an extracting loader from an existing loader. Supports loaders of type { loader: [name]-loader -> {String}, options: {} -> {Object} }.

Multiple Instances

There is also an extract function on the instance. You should use this if you have more than one instance of ExtractJssPlugin.

const ExtractJssPlugin = require('extract-jss-webpack-plugin');

// Create multiple instances
const extractCSS = new ExtractJssPlugin('stylesheets/[name]-one.css');
const extractLESS = new ExtractJssPlugin('stylesheets/[name]-two.css');

module.exports = {
  module: {
    rules: [
      {
        test: /\.css$/,
        use: extractCSS.extract([ 'css-loader', 'postcss-loader' ])
      },
      {
        test: /\.less$/i,
        use: extractLESS.extract([ 'css-loader', 'less-loader' ])
      },
    ]
  },
  plugins: [
    extractCSS,
    extractLESS
  ]
};

Extracting Sass or LESS

The configuration is the same, switch out sass-loader for less-loader when necessary.

const ExtractJssPlugin = require('extract-jss-webpack-plugin');

module.exports = {
  module: {
    rules: [
      {
        test: /\.scss$/,
        use: ExtractJssPlugin.extract({
          fallback: 'style-loader',
          //resolve-url-loader may be chained before sass-loader if necessary
          use: ['css-loader', 'sass-loader']
        })
      }
    ]
  },
  plugins: [
    new ExtractJssPlugin('style.css')
    //if you want to pass in options, you can do so:
    //new ExtractJssPlugin({
    //  filename: 'style.css'
    //})
  ]
}

Modify filename

filename parameter could be Function. It passes getPath to process the format like css/[name].css and returns the real file name, css/js/a.css. You can replace css/js with css then you will get the new path css/a.css.

entry: {
  'js/a': "./a"
},
plugins: [
  new ExtractJssPlugin({
    filename:  (getPath) => {
      return getPath('css/[name].css').replace('css/js', 'css');
    },
    allChunks: true
  })
]