css-magic-split-webpack-plugin

Split your CSS for stupid browsers using webpack and postcss.

Using webpack to generate your CSS is fun for some definitions of fun. Unfortunately the fun stops when you have a large app and need IE9 support because IE9 will ignore any more than ~4000 selectors in your lovely generated CSS bundle. The solution is to split your CSS bundle smartly into multiple smaller CSS files. Now you can.™ Supports source-maps.

The main motivation for adding the split-by-comments feature is to facilitate the ability to split vendor styles from your app's styles. This is especially useful when using SASS or LESS preprocessors. Simply use the appropriate loader for your stylesheet and the plugin will take care of the rest.

Installation

npm install --save css-magic-split-webpack-plugin

Usage

Add split points in your CSS, SASS or LESS stylesheets. Then simply add an instance of CSSSplitWebpackPlugin to your list of plugins in your webpack configuration file after ExtractTextPlugin. That's it!

/*! split:vendor */
@import 'bootstrap.css';

/*! split:app */
@import 'app.css';

var ExtractTextPlugin = require('extract-text-webpack-plugin');
var CSSSplitWebpackPlugin = require('css-magic-split-webpack-plugin').default;

module.exports = {
  entry: './index.js',
  context: __dirname,
  output: {
    path: __dirname + '/dist',
    publicPath: '/foo',
    filename: 'bundle.js',
  },
  module: {
    loaders: [{
      test: /\.css$/,
      loader: ExtractTextPlugin.extract('style-loader', 'css-loader'),
    },{
      test: /\.scss$/,
      loader: ExtractTextPlugin.extract('style-loader', 'css-loader', 'sass-loader'),
    }],
  },
  plugins: [
    new ExtractTextPlugin('styles.css'),
    new CSSSplitWebpackPlugin({size: 4000, commentPattern: '! split:'}),
  ],
};

The following configuration options are available:

size: default: 4000 The maximum number of CSS rules allowed in a single file. To make things work with IE this value should be somewhere around 4000.

bySize: default: true Determines whether or not the file is split by size.

byComment: default: true Determines whether or not the file is to be split by CSS comments.

commentPattern: default: "! split:" The pattern to search for in comments. Example:

imports: default: false If you originally built your app to only ever consider using one CSS file then this flag is for you. It creates an additional CSS file that imports all of the split files. You pass true to turn this feature on, or a string with the name you'd like the generated file to have.

filename: default: "[name]-[part]-[chunkName].[ext]" Control how the split files have their names generated. The default uses the parent's filename and extension, but adds in the part number.

preserve: default: false. Keep the original unsplit file as well. Sometimes this is desirable if you want to target a specific browser (IE) with the split files and then serve the unsplit ones to everyone else.