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extract-css-chunks-webpack-plugin

🍾🍾🍾It's our absolute pleasure to announce Webpack 4 Support 🚀🚀🚀

> HEADLINES (May 2018): Now Independently supports Webpack 4:
> Yep that's right. The universal family is now fully Webpack 4. Thank you to all our users for your loyalty and patience! If you love Universal, then you are gonna fall head over heels when we bring out the main course!

So... why did we rebuild extract-css-chunks-webpack-plugin? What does it offer?

It's got all the goodness of mini-css-extract-plugin but with 2 gleaming, sought after benefits.

Compared to the existing loaders, we are offering a single solution as opposed to needing to depend on multiple loaders to cater for different features:

Perks

- HMR: It also has first-class support for Hot Module Replacement across ALL those css files/chunks!!!
- cacheable stylesheets
- smallest total bytes sent compared to "render-path" css-in-js solutions that include your CSS definitions in JS
- Faster than the V2!
- Async loading
- No duplicate compilation (performance)
- Easier to use
- Specific to CSS
- SSR Friendly development build, focused on frontend DX
- Works seamlessly with the Universal family
- Works fantastically as a standalone style loader (You can use it for any webpack project! with no extra dependencies!)
- Async styles do not render block webkit browsers, if you use the insert option

Additionally, if you are already a user of the universal family -- we will be waving goodbye to the mandatory window.__CSS_CHUNKS__.

The functionality is still available to you via chunk flushing, and it can come in super handy when needing to easily resolve style assets as urls that might need to be passed to a third party.

webpack.config.js

``js
const ExtractCssChunks = require('extract-css-chunks-webpack-plugin');

module.exports = {
plugins: [new ExtractCssChunks()],
module: {
rules: [
{
test: /\.css$/i,
use: [ExtractCssChunks.loader, 'css-loader'],
},
],
},
};
`

Options

$3

Type: String|Function
Default: the publicPath in webpackOptions.output

Specifies a custom public path for the target file(s).

#### String

webpack.config.js

`js
const ExtractCssChunks = require('extract-css-chunks-webpack-plugin');

module.exports = {
plugins: [
new ExtractCssChunks({
// 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: ExtractCssChunks.loader,
options: {
publicPath: '/public/path/to/',
},
},
'css-loader',
],
},
],
},
};
`

#### Function

webpack.config.js

`js
const ExtractCssChunks = require('extract-css-chunks-webpack-plugin');

module.exports = {
plugins: [
new ExtractCssChunks({
// 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: ExtractCssChunks.loader,
options: {
publicPath: (resourcePath, context) => {
return path.relative(path.dirname(resourcePath), context) + '/';
},
},
},
'css-loader',
],
},
],
},
};
`

$3

Type: Boolean
Default: false

By default, extract-css-chunks-webpack-plugin generates JS modules that use the CommonJS modules syntax.
There are some cases in which using ES modules is beneficial, like in the case of module concatenation and tree shaking.

You can enable a ES module syntax using:

webpack.config.js

`js
const ExtractCssChunks = require('extract-css-chunks-webpack-plugin');

module.exports = {
plugins: [new ExtractCssChunks()],
module: {
rules: [
{
test: /\.css$/i,
use: [
{
loader: ExtractCssChunks.loader,
options: {
esModule: true,
},
},
'css-loader',
],
},
],
},
};
`

Examples

$3

webpack.config.js

`js
const ExtractCssChunks = require('extract-css-chunks-webpack-plugin');

module.exports = {
plugins: [
new ExtractCssChunks({
// Options similar to the same options in webpackOptions.output
// all options are optional
filename: '[name].css',
chunkFilename: '[id].css',
ignoreOrder: false, // Enable to remove warnings about conflicting order
}),
],
module: {
rules: [
{
test: /\.css$/,
use: [
{
loader: ExtractCssChunks.loader,
options: {
// you can specify a publicPath here
// by default it uses publicPath in webpackOptions.output
publicPath: '../',
hmr: process.env.NODE_ENV === 'development',
},
},
'css-loader',
],
},
],
},
};
`

$3

webpack.config.js

`js
const ExtractCssChunks = require('extract-css-chunks-webpack-plugin');

module.exports = {
plugins: [
new ExtractCssChunks({
// 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: ExtractCssChunks.loader,
options: {
publicPath: (resourcePath, context) => {
// publicPath is the relative path of the resource to the context
// e.g. for ./css/admin/main.css the publicPath will be ../../
// while for ./css/main.css the publicPath will be ../
return path.relative(path.dirname(resourcePath), context) + '/';
},
},
},
'css-loader',
],
},
],
},
};
`

$3

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 ExtractCssChunks = require('extract-css-chunks-webpack-plugin');
const devMode = process.env.NODE_ENV !== 'production';

module.exports = {
plugins: [
new ExtractCssChunks({
// 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: [
{
loader: ExtractCssChunks.loader,
options: {
hmr: process.env.NODE_ENV === 'development',
},
},
'css-loader',
'postcss-loader',
'sass-loader',
],
},
],
},
};
`

$3

The extract-css-chunks-webpack-plugin supports hot reloading of actual css files in development.
Some options are provided to enable HMR of both standard stylesheets and locally scoped CSS or CSS modules.
Below is an example configuration of extract-css-chunks for HMR use with CSS modules.

While we attempt to hmr css-modules. It is not easy to perform when code-splitting with custom chunk names.
reloadAll is an option that should only be enabled if HMR isn't working correctly.
The core challenge with css-modules is that when code-split, the chunk ids can and do end up different compared to the filename.

webpack.config.js

`js
const ExtractCssChunks = require('extract-css-chunks-webpack-plugin');

module.exports = {
plugins: [
new ExtractCssChunks({
// 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: ExtractCssChunks.loader,
options: {
// only enable hot in development
hmr: process.env.NODE_ENV === 'development',
// if hmr does not work, this is a forceful method.
reloadAll: true,
},
},
'css-loader',
],
},
],
},
};
`

$3

To minify the output, use a plugin like 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 TerserJSPlugin = require('terser-webpack-plugin');
const ExtractCssChunks = require('extract-css-chunks-webpack-plugin');
const OptimizeCSSAssetsPlugin = require('optimize-css-assets-webpack-plugin');

module.exports = {
optimization: {
minimizer: [new TerserJSPlugin({}), new OptimizeCSSAssetsPlugin({})],
},
plugins: [
new ExtractCssChunks({
filename: '[name].css',
chunkFilename: '[id].css',
}),
],
module: {
rules: [
{
test: /\.css$/,
use: [ExtractCssChunks.loader, 'css-loader'],
},
],
},
};
`

$3

The runtime code detects already added CSS via or