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Description

Lightweight CSS extraction plugin

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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 v5 feature and requires webpack 5 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"], }, ], }, };

⚠️ Note that if you import CSS from your webpack entrypoint or import styles in the initial chunk,

mini-css-extract-plugin
will not load this CSS into the page. Please use
html-webpack-plugin
for automatic generation
link
tags or create
index.html
file with
link
tag.

⚠️ Source maps works only for

source-map
/
nosources-source-map
/
hidden-nosources-source-map
/
hidden-source-map
values because CSS only supports source maps with the
sourceMappingURL
comment (i.e.
//# sourceMappingURL=style.css.map
). If you need set
devtool
to another value you can enable source maps generation for extracted CSS using
sourceMap: true
for
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}
|
document.head.appendChild(linkTag);
| Inserts the
link
tag at the given position for non-initial (async) CSS chunks | |
attributes
|
{Object}
|
{}
| Adds custom attributes to the
link
tag for non-initial (async) CSS chunks | |
linkType
|
{String\|Boolean}
|
text/css
| Allows loading asynchronous chunks with a custom link type | |
runtime
|
{Boolean}
|
true
| Allows to enable/disable the runtime generation | |
experimentalUseImportModule
|
{Boolean}
|
undefined
| Use an experimental webpack API to execute modules instead of child compilers |

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:
document.head.appendChild(linkTag);

⚠️ Only for non-initial (async) chunks.

By default, the

mini-css-extract-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 insertion. 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:
{}

⚠️ Only for non-initial (async) chunks.

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

linkType

Type:

String|Boolean
Default:
text/css

This option allows loading asynchronous chunks with a custom link type, such as

.

String

Possible values:

text/css

webpack.config.js

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

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

Boolean

false
disables the link
type
attribute

webpack.config.js

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

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

runtime

Type:

Boolean
Default:
true

Allows to enable/disable the runtime generation. CSS will be still extracted and can be used for a custom loading methods. For example, you can use assets-webpack-plugin to retreive them then use your own runtime code to download assets when needed.

true
to skip.

webpack.config.js

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

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

experimentalUseImportModule

Type:

Boolean
Default:
undefined

Enabled by default if not explicitly enabled (i.e.

true
and
false
allow you to explicitly control this option) and new API is available (at least webpack
5.52.0
is required). Boolean values are available since version
5.33.2
, but you need to enable
experiments.executeModule
(not required from webpack
5.52.0
).

Use a new webpack API to execute modules instead of child compilers. This improves performance and memory usage a lot.

When combined with

experiments.layers
, this adds a
layer
option to the loader options to specify the layer of the css execution.

webpack.config.js

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

module.exports = { plugins: [ new MiniCssExtractPlugin({ // You don't need this for >= 5.52.0 due to the fact that this is enabled by default // Required only for >= 5.33.2 & <= 5.52.0 // Not avaliable/unsafe for <= 5.33.2 experimentalUseImportModule: true, }), ], module: { rules: [ { test: /.css$/i, use: [MiniCssExtractPlugin.loader, "css-loader"], }, ], }, };

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 | |
emit
|
{Boolean}
|
true
| If false, the plugin will extract the CSS but will not emit the file | |
esModule
|
{Boolean}
|
true
| Use ES modules syntax |

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", ], }, ], }, };

emit

Type:

Boolean
Default:
true

If true, emits a file (writes a file to the filesystem). If false, the plugin will extract the CSS but will not emit the file. It is often useful to disable this option for server-side packages.

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", ], }, ], }, };

Examples

Recommend

For

production
builds it's recommended to extract the CSS from your bundle being able to use parallel loading of CSS/JS resources later on. This can be achieved by using the
mini-css-extract-plugin
, because it creates 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";

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

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", ], }, ], }, };

Named export for CSS Modules

⚠ 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
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, }, { loader: "css-loader", options: { esModule: true, modules: { namedExport: true, localIdentName: "foo__[name]__[local]", }, }, }, ], }, ], }, };

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", type: "css/mini-extract", chunks: "all", enforce: true, }, }, }, }, plugins: [ new MiniCssExtractPlugin({ filename: "[name].css", }), ], module: { rules: [ { test: /.css$/, use: [MiniCssExtractPlugin.loader, "css-loader"], }, ], }, };

Note that

type
should be used instead of
test
in Webpack 5, or else an extra
.js
file can be generated besides the
.css
file. This is because
test
doesn't know which modules should be dropped (in this case, it won't detect that
.js
should be dropped).

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");

module.exports = { entry: { foo: path.resolve(__dirname, "src/foo"), bar: path.resolve(__dirname, "src/bar"), }, optimization: { splitChunks: { cacheGroups: { fooStyles: { type: "css/mini-extract", name: "styles_foo", chunks: (chunk) => { return chunk.name === "foo"; }, enforce: true, }, barStyles: { type: "css/mini-extract", name: "styles_bar", chunks: (chunk) => { return chunk.name === "bar"; }, 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"], }, ], }, };

Multiple Themes

webpack.config.js

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

module.exports = { entry: "./src/index.js", module: { rules: [ { test: /.s[ac]ss$/i, oneOf: [ { resourceQuery: "?dark", use: [ Self.loader, "css-loader", { loader: "sass-loader", options: { additionalData: @use 'dark-theme/vars' as vars;, }, }, ], }, { use: [ Self.loader, "css-loader", { loader: "sass-loader", options: { additionalData: @use 'light-theme/vars' as vars;, }, }, ], }, ], }, ], }, plugins: [ new Self({ filename: "[name].css", attributes: { id: "theme", }, }), ], };

src/index.js

import "./style.scss";

let theme = "light"; const themes = {};

themes[theme] = document.querySelector("#theme");

async function loadTheme(newTheme) { // eslint-disable-next-line no-console console.log(CHANGE THEME - ${newTheme});

const themeElement = document.querySelector("#theme");

if (themeElement) { themeElement.remove(); }

if (themes[newTheme]) { // eslint-disable-next-line no-console console.log(THEME ALREADY LOADED - ${newTheme});

document.head.appendChild(themes[newTheme]);

return;

}

if (newTheme === "dark") { // eslint-disable-next-line no-console console.log(LOADING THEME - ${newTheme});

import(/* webpackChunkName: "dark" */ "./style.scss?dark").then(() => {
  themes[newTheme] = document.querySelector("#theme");

  // eslint-disable-next-line no-console
  console.log(`LOADED - ${newTheme}`);
});

} }

document.onclick = () => { if (theme === "light") { theme = "dark"; } else { theme = "light"; }

loadTheme(theme); };

src/dark-theme/_vars.scss

$background: black;

src/light-theme/_vars.scss

$background: white;

src/styles.scss

body {
  background-color: vars.$background;
}

public/index.html

<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>Document</title>
<link id="theme" rel="stylesheet" type="text/css" href="./main.css">


<script src="./main.js"></script>

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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