mini-css-extract-plugin

by webpack-contrib

webpack-contrib / mini-css-extract-plugin

Lightweight CSS extraction plugin

4.1K Stars 335 Forks Last release: 1 day ago (v1.1.1) MIT License 182 Commits 25 Releases

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mini-css-extract-plugin

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mini-css-extract-plugin

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

Getting Started

To begin, you'll need to install

mini-css-extract-plugin
:
npm install --save-dev mini-css-extract-plugin

It's recommended to combine

mini-css-extract-plugin
with the
css-loader

Then add the loader and the plugin to your

webpack
config. For example:

style.css

body {
  background: green;
}

component.js

import './style.css';

webpack.config.js

const MiniCssExtractPlugin = require('mini-css-extract-plugin');

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

Options

Plugin Options

| Name | Type | Default | Description | | :-----------------------------------: | :------------------: | :------------------------------------------------------------------------------: | :------------------------------------------------------- | |

filename
|

{String\|Function}
|
[name].css
| This option determines the name of each output CSS file | |
chunkFilename
|
{String\|Function}
|
based on filename
| This option determines the name of non-entry chunk files | |
ignoreOrder
|
{Boolean}
|
false
| Remove Order Warnings | |
insert
|
{String\|Function}
|
var head = document.getElementsByTagName("head")[0];head.appendChild(linkTag);
| Inserts
 at the given position                   |
|    
attributes
|
{Object}
|
{}
| Adds custom attributes to tag |

filename

Type:

String|Function
Default:
[name].css

This option determines the name of each output CSS file.

Works like

output.filename

chunkFilename

Type:

String|Function
Default:
based on filename

i Specifying

chunkFilename
as a
function
is only available in [email protected]

This option determines the name of non-entry chunk files.

Works like

output.chunkFilename

ignoreOrder

Type:

Boolean
Default:
false

Remove Order Warnings. See examples below for details.

insert

Type:

String|Function
Default:
var head = document.getElementsByTagName("head")[0]; head.appendChild(linkTag);

By default, the

extract-css-chunks-plugin
appends styles (
 elements) to 
document.head
of the current
window
.

However in some circumstances it might be necessary to have finer control over the append target or even delay

link
elements instertion. For example this is the case when you asynchronously load styles for an application that runs inside of an iframe. In such cases
insert
can be configured to be a function or a custom selector.

If you target an iframe make sure that the parent document has sufficient access rights to reach into the frame document and append elements to it.

String

Allows to setup custom query selector. A new

 element will be inserted after the found item.

webpack.config.js

new MiniCssExtractPlugin({
  insert: '#some-element',
});

A new

 element will be inserted after the element with id 
some-element
.
Function

Allows to override default behavior and insert styles at any position.

⚠ Do not forget that this code will run in the browser alongside your application. Since not all browsers support latest ECMA features like

let
,
const
,
arrow function expression
and etc we recommend you to use only ECMA 5 features and syntax.

⚠ The

insert
function is serialized to string and passed to the plugin. This means that it won't have access to the scope of the webpack configuration module.

webpack.config.js

new MiniCssExtractPlugin({
  insert: function (linkTag) {
    var reference = document.querySelector('#some-element');
    if (reference) {
      reference.parentNode.insertBefore(linkTag, reference);
    }
  },
});

A new

 element will be inserted before the element with id 
some-element
.

attributes

Type:

Object
Default:
{}

If defined, the

mini-css-extract-plugin
will attach given attributes with their values on element.

webpack.config.js

const MiniCssExtractPlugin = require('mini-css-extract-plugin');

module.exports = { plugins: [ new MiniCssExtractPlugin({ attributes: { id: 'target', 'data-target': 'example', }, }), ], module: { rules: [ { test: /.css$/i, use: [MiniCssExtractPlugin.loader, 'css-loader'], }, ], }, };

Note: It's only applied to dynamically loaded css chunks, if you want to modify link attributes inside html file, please using html-webpack-plugin

Loader Options

| Name | Type | Default | Description | | :-----------------------------: | :------------------: | :--------------------------------: | :-------------------------------------------------------------------------------- | |

publicPath
|

{String\|Function}
|
webpackOptions.output.publicPath
| Specifies a custom public path for the external resources like images, files, etc | |
esModule
|
{Boolean}
|
true
| Use ES modules syntax | |
modules
|
{Object}
|
undefined
| Configuration CSS Modules |

publicPath

Type:

String|Function
Default: the
publicPath
in
webpackOptions.output

Specifies a custom public path for the external resources like images, files, etc inside

CSS
. Works like
output.publicPath
String

webpack.config.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: { publicPath: '/public/path/to/', }, }, 'css-loader', ], }, ], }, };

Function

webpack.config.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: { publicPath: (resourcePath, context) => { return path.relative(path.dirname(resourcePath), context) + '/'; }, }, }, 'css-loader', ], }, ], }, };

esModule

Type:

Boolean
Default:
true

By default,

mini-css-extract-plugin
generates JS modules that use the ES 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 CommonJS syntax using:

webpack.config.js

const MiniCssExtractPlugin = require('mini-css-extract-plugin');

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

modules

Type:

Object
Default:
undefined

Configuration CSS Modules.

namedExport

Type:

Boolean
Default:
false

Enables/disables ES modules named export for locals.

⚠ Names of locals are converted to

camelCase
.

⚠ It is not allowed to use JavaScript reserved words in css class names.

⚠ Options

esModule
and
modules.namedExport
in
css-loader
and
MiniCssExtractPlugin.loader
should be enabled.

styles.css

.foo-baz {
  color: red;
}
.bar {
  color: blue;
}

index.js

import { fooBaz, bar } from './styles.css';

console.log(fooBaz, bar);

You can enable a ES module named export using:

webpack.config.js

const MiniCssExtractPlugin = require('mini-css-extract-plugin');

module.exports = { plugins: [new MiniCssExtractPlugin()], module: { rules: [ { test: /.css$/, use: [ { loader: MiniCssExtractPlugin.loader, options: { esModule: true, modules: { namedExport: true, }, }, }, { loader: 'css-loader', options: { esModule: true, modules: { namedExport: true, localIdentName: 'foo__[name]__[local]', }, }, }, ], }, ], }, };

Examples

Minimal example

webpack.config.js

const MiniCssExtractPlugin = require('mini-css-extract-plugin');

module.exports = { plugins: [ new MiniCssExtractPlugin({ // 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: MiniCssExtractPlugin.loader, options: { // you can specify a publicPath here // by default it uses publicPath in webpackOptions.output publicPath: '../', }, }, 'css-loader', ], }, ], }, };

Common use case

mini-css-extract-plugin
is more often used in
production
mode to get separate css files. For
development
mode (including
webpack-dev-server
) you can use
style-loader
, because it injects CSS into the DOM using multiple and works faster.

i Do not use together

style-loader
and
mini-css-extract-plugin
.

webpack.config.js

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

const plugins = []; if (!devMode) { // enable in production only plugins.push(new MiniCssExtractPlugin()); }

module.exports = { plugins, module: { rules: [ { test: /.(sa|sc|c)ss$/, use: [ devMode ? 'style-loader' : MiniCssExtractPlugin.loader, 'css-loader', 'postcss-loader', 'sass-loader', ], }, ], }, };

The
publicPath
option as function

webpack.config.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: { 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', ], }, ], }, };

Advanced configuration example

This plugin should not be used with

style-loader
in the loaders chain.

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.)

You should not use

HotModuleReplacementPlugin
plugin if you are using a
webpack-dev-server
.
webpack-dev-server
enables / disables HMR using
hot
option.

webpack.config.js

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

const plugins = [ new MiniCssExtractPlugin({ // Options similar to the same options in webpackOptions.output // both options are optional filename: devMode ? '[name].css' : '[name].[contenthash].css', chunkFilename: devMode ? '[id].css' : '[id].[contenthash].css', }), ]; if (devMode) { // only enable hot in development plugins.push(new webpack.HotModuleReplacementPlugin()); }

module.exports = { plugins, module: { rules: [ { test: /.(sa|sc|c)ss$/, use: [ MiniCssExtractPlugin.loader, 'css-loader', 'postcss-loader', 'sass-loader', ], }, ], }, };

Hot Module Reloading (HMR)

Note: HMR is automatically supported in webpack 5. No need to configure it. Skip the following:

The

mini-css-extract-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 mini-css for HMR use with CSS modules.

You should not use

HotModuleReplacementPlugin
plugin if you are using a
webpack-dev-server
.
webpack-dev-server
enables / disables HMR using
hot
option.

webpack.config.js

const webpack = require('webpack');
const MiniCssExtractPlugin = require('mini-css-extract-plugin');

const plugins = [ new MiniCssExtractPlugin({ // Options similar to the same options in webpackOptions.output // both options are optional filename: devMode ? '[name].css' : '[name].[contenthash].css', chunkFilename: devMode ? '[id].css' : '[id].[contenthash].css', }), ]; if (devMode) { // only enable hot in development plugins.push(new webpack.HotModuleReplacementPlugin()); }

module.exports = { plugins, module: { rules: [ { test: /.css$/, use: [ { loader: MiniCssExtractPlugin.loader, options: {}, }, 'css-loader', ], }, ], }, };

Minimizing For Production

To minify the output, use a plugin like css-minimizer-webpack-plugin.

webpack.config.js

const MiniCssExtractPlugin = require('mini-css-extract-plugin');
const CssMinimizerPlugin = require('css-minimizer-webpack-plugin');

module.exports = { plugins: [ new MiniCssExtractPlugin({ filename: '[name].css', chunkFilename: '[id].css', }), ], module: { rules: [ { test: /.css$/, use: [MiniCssExtractPlugin.loader, 'css-loader'], }, ], }, optimization: { minimizer: [ // For [email protected] you can use the ... syntax to extend existing minimizers (i.e. terser-webpack-plugin), uncomment the next line // ... new CssMinimizerPlugin(), ], }, };

This will enable CSS optimization only in production mode. If you want to run it also in development set the

optimization.minimize
option to true.

Using preloaded or inlined CSS

The runtime code detects already added CSS via

 or 
 tag.
This can be useful when injecting CSS on server-side for Server-Side-Rendering.
The 
href
of the
 tag has to match the URL that will be used for loading the CSS chunk.
The 
data-href
attribute can be used for
 and 
 too.
When inlining CSS 
data-href
must be used.

Extracting all CSS in a single file

The CSS can be extracted in one CSS file using

optimization.splitChunks.cacheGroups
.

webpack.config.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.

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

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

const chunks = m.getChunks(); // For [email protected] chunks = m._chunks

for (const chunk of chunks) { return chunk.name; }

return false; }

module.exports = { entry: { foo: path.resolve(__dirname, 'src/foo'), bar: path.resolve(__dirname, 'src/bar'), }, optimization: { splitChunks: { cacheGroups: { fooStyles: { name: 'styles_foo', test: (m, c, entry = 'foo') => m.constructor.name === 'CssModule' && recursiveIssuer(m) === entry, chunks: 'all', enforce: true, }, barStyles: { name: 'styles_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'], }, ], }, };

Filename Option as function

With the

filename
option you can use chunk data to customize the filename. This is particularly useful when dealing with multiple entry points and wanting to get more control out of the filename for a given entry point/chunk. In the example below, we'll use
filename
to output the generated css into a different directory.

webpack.config.js

const MiniCssExtractPlugin = require('mini-css-extract-plugin');

module.exports = { plugins: [ new MiniCssExtractPlugin({ filename: ({ chunk }) => ${chunk.name.replace('/js/', '/css/')}.css, }), ], module: { rules: [ { test: /.css$/, use: [MiniCssExtractPlugin.loader, 'css-loader'], }, ], }, };

Long Term Caching

For long term caching use

filename: "[contenthash].css"
. Optionally add
[name]
.

webpack.config.js

const MiniCssExtractPlugin = require('mini-css-extract-plugin');

module.exports = { plugins: [ new MiniCssExtractPlugin({ filename: '[name].[contenthash].css', chunkFilename: '[id].[contenthash].css', }), ], module: { rules: [ { test: /.css$/, use: [MiniCssExtractPlugin.loader, 'css-loader'], }, ], }, };

Remove Order Warnings

For projects where css ordering has been mitigated through consistent use of scoping or naming conventions, the css order warnings can be disabled by setting the ignoreOrder flag to true for the plugin.

webpack.config.js

const MiniCssExtractPlugin = require('mini-css-extract-plugin');

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

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:

Contributing

Please take a moment to read our contributing guidelines if you haven't yet done so.

CONTRIBUTING

License

MIT

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