2043 lines
45 KiB
Markdown
2043 lines
45 KiB
Markdown
<div align="center">
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<img width="180" height="180" vspace="20"
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src="https://cdn.worldvectorlogo.com/logos/css-3.svg">
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<a href="https://github.com/webpack/webpack">
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<img width="200" height="200"
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src="https://webpack.js.org/assets/icon-square-big.svg">
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</a>
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</div>
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[![npm][npm]][npm-url]
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[![node][node]][node-url]
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[![tests][tests]][tests-url]
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[![coverage][cover]][cover-url]
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[![discussion][discussion]][discussion-url]
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[![size][size]][size-url]
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# css-loader
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The `css-loader` interprets `@import` and `url()` like `import/require()` and will resolve them.
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## Getting Started
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> **Warning**
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>
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> To use the latest version of css-loader, webpack@5 is required
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To begin, you'll need to install `css-loader`:
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```console
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npm install --save-dev css-loader
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```
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or
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```console
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yarn add -D css-loader
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```
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or
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```console
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pnpm add -D css-loader
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```
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Then add the plugin to your `webpack` config. For example:
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**file.js**
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```js
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import css from "file.css";
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```
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**webpack.config.js**
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```js
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module.exports = {
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module: {
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rules: [
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{
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test: /\.css$/i,
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use: ["style-loader", "css-loader"],
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},
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],
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},
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};
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```
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And run `webpack` via your preferred method.
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If, for one reason or another, you need to extract CSS as a file (i.e. do not store CSS in a JS module) you might want to check out the [recommend example](https://github.com/webpack-contrib/css-loader#recommend).
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## Options
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- **[`url`](#url)**
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- **[`import`](#import)**
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- **[`modules`](#modules)**
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- **[`sourceMap`](#sourcemap)**
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- **[`importLoaders`](#importloaders)**
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- **[`esModule`](#esmodule)**
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- **[`exportType`](#exporttype)**
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### `url`
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Type:
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```ts
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type url =
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| boolean
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| {
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filter: (url: string, resourcePath: string) => boolean;
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};
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```
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Default: `true`
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Allow to enable/disables handling the CSS functions `url` and `image-set`.
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If set to `false`, `css-loader` will not parse any paths specified in `url` or `image-set`.
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A function can also be passed to control this behavior dynamically based on the path to the asset.
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Starting with version [4.0.0](https://github.com/webpack-contrib/css-loader/blob/master/CHANGELOG.md#400-2020-07-25), absolute paths are parsed based on the server root.
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Examples resolutions:
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```js
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url(image.png) => require('./image.png')
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url('image.png') => require('./image.png')
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url(./image.png) => require('./image.png')
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url('./image.png') => require('./image.png')
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url('http://dontwritehorriblecode.com/2112.png') => require('http://dontwritehorriblecode.com/2112.png')
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image-set(url('image2x.png') 1x, url('image1x.png') 2x) => require('./image1x.png') and require('./image2x.png')
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```
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To import assets from a `node_modules` path (include `resolve.modules`) and for `alias`, prefix it with a `~`:
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```js
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url(~module/image.png) => require('module/image.png')
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url('~module/image.png') => require('module/image.png')
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url(~aliasDirectory/image.png) => require('otherDirectory/image.png')
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```
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#### `boolean`
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Enable/disable `url()` resolving.
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**webpack.config.js**
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```js
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module.exports = {
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module: {
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rules: [
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{
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test: /\.css$/i,
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loader: "css-loader",
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options: {
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url: true,
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},
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},
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],
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},
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};
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```
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#### `object`
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Allow to filter `url()`. All filtered `url()` will not be resolved (left in the code as they were written).
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**webpack.config.js**
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```js
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module.exports = {
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module: {
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rules: [
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{
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test: /\.css$/i,
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loader: "css-loader",
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options: {
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url: {
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filter: (url, resourcePath) => {
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// resourcePath - path to css file
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// Don't handle `img.png` urls
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if (url.includes("img.png")) {
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return false;
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}
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// Don't handle images under root-relative /external_images/
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if (/^\/external_images\//.test(path)) {
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return false;
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}
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return true;
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},
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},
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},
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},
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],
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},
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};
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```
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### `import`
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Type:
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<!-- use other name to prettify since import is reserved keyword -->
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```ts
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type importFn =
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| boolean
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| {
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filter: (
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url: string,
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media: string,
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resourcePath: string,
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supports?: string,
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layer?: string
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) => boolean;
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};
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```
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Default: `true`
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Allows to enables/disables `@import` at-rules handling.
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Control `@import` resolving. Absolute urls in `@import` will be moved in runtime code.
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Examples resolutions:
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```
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@import 'style.css' => require('./style.css')
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@import url(style.css) => require('./style.css')
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@import url('style.css') => require('./style.css')
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@import './style.css' => require('./style.css')
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@import url(./style.css) => require('./style.css')
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@import url('./style.css') => require('./style.css')
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@import url('http://dontwritehorriblecode.com/style.css') => @import url('http://dontwritehorriblecode.com/style.css') in runtime
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```
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To import styles from a `node_modules` path (include `resolve.modules`) and for `alias`, prefix it with a `~`:
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```
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@import url(~module/style.css) => require('module/style.css')
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@import url('~module/style.css') => require('module/style.css')
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@import url(~aliasDirectory/style.css) => require('otherDirectory/style.css')
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```
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#### `boolean`
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Enable/disable `@import` resolving.
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**webpack.config.js**
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```js
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module.exports = {
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module: {
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rules: [
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{
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test: /\.css$/i,
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loader: "css-loader",
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options: {
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import: true,
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},
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},
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],
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},
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};
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```
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#### `object`
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##### `filter`
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Type:
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```ts
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type filter = (url: string, media: string, resourcePath: string) => boolean;
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```
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Default: `undefined`
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Allow to filter `@import`. All filtered `@import` will not be resolved (left in the code as they were written).
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**webpack.config.js**
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```js
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module.exports = {
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module: {
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rules: [
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{
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test: /\.css$/i,
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loader: "css-loader",
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options: {
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import: {
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filter: (url, media, resourcePath) => {
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// resourcePath - path to css file
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// Don't handle `style.css` import
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if (url.includes("style.css")) {
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return false;
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}
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return true;
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},
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},
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},
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},
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],
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},
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};
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```
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### `modules`
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Type:
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```ts
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type modules =
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| boolean
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| "local"
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| "global"
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| "pure"
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| "icss"
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| {
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auto: boolean | regExp | ((resourcePath: string) => boolean);
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mode:
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| "local"
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| "global"
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| "pure"
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| "icss"
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| ((resourcePath) => "local" | "global" | "pure" | "icss");
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localIdentName: string;
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localIdentContext: string;
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localIdentHashSalt: string;
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localIdentHashFunction: string;
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localIdentHashDigest: string;
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localIdentRegExp: string | regExp;
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getLocalIdent: (
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context: LoaderContext,
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localIdentName: string,
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localName: string
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) => string;
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namedExport: boolean;
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exportGlobals: boolean;
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exportLocalsConvention:
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| "asIs"
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| "camelCase"
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| "camelCaseOnly"
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| "dashes"
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| "dashesOnly"
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| ((name: string) => string);
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exportOnlyLocals: boolean;
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};
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```
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Default: `undefined`
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Allows to enable/disable CSS Modules or ICSS and setup configuration:
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- `undefined` - enable CSS modules for all files matching `/\.module\.\w+$/i.test(filename)` and `/\.icss\.\w+$/i.test(filename)` regexp.
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- `true` - enable CSS modules for all files.
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- `false` - disables CSS Modules for all files.
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- `string` - disables CSS Modules for all files and set the `mode` option, more information you can read [here](https://github.com/webpack-contrib/css-loader#mode)
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- `object` - enable CSS modules for all files, if `modules.auto` option is not specified, otherwise the `modules.auto` option will determine whether if it is CSS modules or not, more information you can read [here](https://github.com/webpack-contrib/css-loader#auto)
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The `modules` option enables/disables the **[CSS Modules](https://github.com/css-modules/css-modules)** specification and setup basic behaviour.
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Using `false` value increase performance because we avoid parsing **CSS Modules** features, it will be useful for developers who use vanilla css or use other technologies.
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**webpack.config.js**
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```js
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module.exports = {
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module: {
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rules: [
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{
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test: /\.css$/i,
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loader: "css-loader",
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options: {
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modules: true,
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},
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},
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],
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},
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};
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```
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#### `Features`
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##### `Scope`
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Using `local` value requires you to specify `:global` classes.
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Using `global` value requires you to specify `:local` classes.
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Using `pure` value requires selectors must contain at least one local class or id.
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You can find more information [here](https://github.com/css-modules/css-modules).
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Styles can be locally scoped to avoid globally scoping styles.
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The syntax `:local(.className)` can be used to declare `className` in the local scope. The local identifiers are exported by the module.
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With `:local` (without brackets) local mode can be switched on for this selector.
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The `:global(.className)` notation can be used to declare an explicit global selector.
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With `:global` (without brackets) global mode can be switched on for this selector.
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The loader replaces local selectors with unique identifiers. The chosen unique identifiers are exported by the module.
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```css
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:local(.className) {
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background: red;
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}
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:local .className {
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color: green;
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}
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:local(.className .subClass) {
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color: green;
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}
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:local .className .subClass :global(.global-class-name) {
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color: blue;
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}
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```
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```css
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._23_aKvs-b8bW2Vg3fwHozO {
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background: red;
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}
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._23_aKvs-b8bW2Vg3fwHozO {
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color: green;
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}
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._23_aKvs-b8bW2Vg3fwHozO ._13LGdX8RMStbBE9w-t0gZ1 {
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color: green;
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}
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._23_aKvs-b8bW2Vg3fwHozO ._13LGdX8RMStbBE9w-t0gZ1 .global-class-name {
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color: blue;
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}
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```
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> **Note**
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>
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> Identifiers are exported
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```js
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exports.locals = {
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className: "_23_aKvs-b8bW2Vg3fwHozO",
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subClass: "_13LGdX8RMStbBE9w-t0gZ1",
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};
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```
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CamelCase is recommended for local selectors. They are easier to use within the imported JS module.
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You can use `:local(#someId)`, but this is not recommended. Use classes instead of ids.
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##### `Composing`
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When declaring a local classname you can compose a local class from another local classname.
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```css
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:local(.className) {
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background: red;
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color: yellow;
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}
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:local(.subClass) {
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composes: className;
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background: blue;
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}
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```
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This doesn't result in any change to the CSS itself but exports multiple classnames.
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```js
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exports.locals = {
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className: "_23_aKvs-b8bW2Vg3fwHozO",
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subClass: "_13LGdX8RMStbBE9w-t0gZ1 _23_aKvs-b8bW2Vg3fwHozO",
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};
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```
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```css
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._23_aKvs-b8bW2Vg3fwHozO {
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background: red;
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color: yellow;
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}
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._13LGdX8RMStbBE9w-t0gZ1 {
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background: blue;
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}
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```
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##### `Importing`
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To import a local classname from another module.
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> **Note**
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>
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> We strongly recommend that you specify the extension when importing a file, since it is possible to import a file with any extension and it is not known in advance which file to use.
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```css
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:local(.continueButton) {
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composes: button from "library/button.css";
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background: red;
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}
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```
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```css
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:local(.nameEdit) {
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composes: edit highlight from "./edit.css";
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background: red;
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}
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```
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To import from multiple modules use multiple `composes:` rules.
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```css
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:local(.className) {
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composes: edit highlight from "./edit.css";
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composes: button from "module/button.css";
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composes: classFromThisModule;
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background: red;
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}
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```
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##### `Values`
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You can use `@value` to specific values to be reused throughout a document.
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We recommend use prefix `v-` for values, `s-` for selectors and `m-` for media at-rules.
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```css
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@value v-primary: #BF4040;
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@value s-black: black-selector;
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@value m-large: (min-width: 960px);
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.header {
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color: v-primary;
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padding: 0 10px;
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}
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.s-black {
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color: black;
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}
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@media m-large {
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.header {
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padding: 0 20px;
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}
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}
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```
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|
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#### `boolean`
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Enable **CSS Modules** features.
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|
|
**webpack.config.js**
|
|
|
|
```js
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module.exports = {
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module: {
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rules: [
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{
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test: /\.css$/i,
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loader: "css-loader",
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options: {
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modules: true,
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},
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},
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],
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},
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};
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```
|
|
|
|
#### `string`
|
|
|
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Enable **CSS Modules** features and setup `mode`.
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|
|
**webpack.config.js**
|
|
|
|
```js
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module.exports = {
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module: {
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rules: [
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{
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test: /\.css$/i,
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loader: "css-loader",
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options: {
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// Using `local` value has same effect like using `modules: true`
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modules: "global",
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},
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},
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],
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},
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};
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```
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|
|
#### `object`
|
|
|
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Enable **CSS Modules** features and setup options for them.
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|
|
|
**webpack.config.js**
|
|
|
|
```js
|
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module.exports = {
|
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module: {
|
|
rules: [
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{
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test: /\.css$/i,
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loader: "css-loader",
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options: {
|
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modules: {
|
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mode: "local",
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auto: true,
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exportGlobals: true,
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localIdentName: "[path][name]__[local]--[hash:base64:5]",
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localIdentContext: path.resolve(__dirname, "src"),
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localIdentHashSalt: "my-custom-hash",
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namedExport: true,
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exportLocalsConvention: "camelCase",
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exportOnlyLocals: false,
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},
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},
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},
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],
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},
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};
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```
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|
|
##### `auto`
|
|
|
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Type:
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|
|
|
```ts
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|
type auto = boolean | regExp | ((resourcePath: string) => boolean);
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|
```
|
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|
|
Default: `undefined`
|
|
|
|
Allows auto enable CSS modules/ICSS based on filename when `modules` option is object.
|
|
|
|
Possible values:
|
|
|
|
- `undefined` - enable CSS modules for all files.
|
|
- `true` - enable CSS modules for all files matching `/\.module\.\w+$/i.test(filename)` and `/\.icss\.\w+$/i.test(filename)` regexp.
|
|
- `false` - disables CSS Modules.
|
|
- `RegExp` - enable CSS modules for all files matching `/RegExp/i.test(filename)` regexp.
|
|
- `function` - enable CSS Modules for files based on the filename satisfying your filter function check.
|
|
|
|
###### `boolean`
|
|
|
|
Possible values:
|
|
|
|
- `true` - enables CSS modules or interoperable CSS format, sets the [`modules.mode`](#mode) option to `local` value for all files which satisfy `/\.module(s)?\.\w+$/i.test(filename)` condition or sets the [`modules.mode`](#mode) option to `icss` value for all files which satisfy `/\.icss\.\w+$/i.test(filename)` condition
|
|
- `false` - disables CSS modules or interoperable CSS format based on filename
|
|
|
|
**webpack.config.js**
|
|
|
|
```js
|
|
module.exports = {
|
|
module: {
|
|
rules: [
|
|
{
|
|
test: /\.css$/i,
|
|
loader: "css-loader",
|
|
options: {
|
|
modules: {
|
|
auto: true,
|
|
},
|
|
},
|
|
},
|
|
],
|
|
},
|
|
};
|
|
```
|
|
|
|
###### `RegExp`
|
|
|
|
Enable CSS modules for files based on the filename satisfying your regex check.
|
|
|
|
**webpack.config.js**
|
|
|
|
```js
|
|
module.exports = {
|
|
module: {
|
|
rules: [
|
|
{
|
|
test: /\.css$/i,
|
|
loader: "css-loader",
|
|
options: {
|
|
modules: {
|
|
auto: /\.custom-module\.\w+$/i,
|
|
},
|
|
},
|
|
},
|
|
],
|
|
},
|
|
};
|
|
```
|
|
|
|
###### `function`
|
|
|
|
Enable CSS modules for files based on the filename satisfying your filter function check.
|
|
|
|
**webpack.config.js**
|
|
|
|
```js
|
|
module.exports = {
|
|
module: {
|
|
rules: [
|
|
{
|
|
test: /\.css$/i,
|
|
loader: "css-loader",
|
|
options: {
|
|
modules: {
|
|
auto: (resourcePath) => resourcePath.endsWith(".custom-module.css"),
|
|
},
|
|
},
|
|
},
|
|
],
|
|
},
|
|
};
|
|
```
|
|
|
|
##### `mode`
|
|
|
|
Type:
|
|
|
|
```ts
|
|
type mode =
|
|
| "local"
|
|
| "global"
|
|
| "pure"
|
|
| "icss"
|
|
| ((resourcePath: string) => "local" | "global" | "pure" | "icss");
|
|
```
|
|
|
|
Default: `'local'`
|
|
|
|
Setup `mode` option. You can omit the value when you want `local` mode.
|
|
|
|
Controls the level of compilation applied to the input styles.
|
|
|
|
The `local`, `global`, and `pure` handles `class` and `id` scoping and `@value` values.
|
|
The `icss` will only compile the low level `Interoperable CSS` format for declaring `:import` and `:export` dependencies between CSS and other languages.
|
|
|
|
ICSS underpins CSS Module support, and provides a low level syntax for other tools to implement CSS-module variations of their own.
|
|
|
|
###### `string`
|
|
|
|
Possible values - `local`, `global`, `pure`, and `icss`.
|
|
|
|
**webpack.config.js**
|
|
|
|
```js
|
|
module.exports = {
|
|
module: {
|
|
rules: [
|
|
{
|
|
test: /\.css$/i,
|
|
loader: "css-loader",
|
|
options: {
|
|
modules: {
|
|
mode: "global",
|
|
},
|
|
},
|
|
},
|
|
],
|
|
},
|
|
};
|
|
```
|
|
|
|
###### `function`
|
|
|
|
Allows set different values for the `mode` option based on a filename
|
|
|
|
Possible return values - `local`, `global`, `pure` and `icss`.
|
|
|
|
**webpack.config.js**
|
|
|
|
```js
|
|
module.exports = {
|
|
module: {
|
|
rules: [
|
|
{
|
|
test: /\.css$/i,
|
|
loader: "css-loader",
|
|
options: {
|
|
modules: {
|
|
// Callback must return "local", "global", or "pure" values
|
|
mode: (resourcePath) => {
|
|
if (/pure.css$/i.test(resourcePath)) {
|
|
return "pure";
|
|
}
|
|
|
|
if (/global.css$/i.test(resourcePath)) {
|
|
return "global";
|
|
}
|
|
|
|
return "local";
|
|
},
|
|
},
|
|
},
|
|
},
|
|
],
|
|
},
|
|
};
|
|
```
|
|
|
|
##### `localIdentName`
|
|
|
|
Type:
|
|
|
|
```ts
|
|
type localIdentName = string;
|
|
```
|
|
|
|
Default: `'[hash:base64]'`
|
|
|
|
Allows to configure the generated local ident name.
|
|
|
|
For more information on options see:
|
|
|
|
- [webpack template strings](https://webpack.js.org/configuration/output/#template-strings),
|
|
- [output.hashDigest](https://webpack.js.org/configuration/output/#outputhashdigest),
|
|
- [output.hashDigestLength](https://webpack.js.org/configuration/output/#outputhashdigestlength),
|
|
- [output.hashFunction](https://webpack.js.org/configuration/output/#outputhashfunction),
|
|
- [output.hashSalt](https://webpack.js.org/configuration/output/#outputhashsalt).
|
|
|
|
Supported template strings:
|
|
|
|
- `[name]` the basename of the resource
|
|
- `[folder]` the folder the resource relative to the `compiler.context` option or `modules.localIdentContext` option.
|
|
- `[path]` the path of the resource relative to the `compiler.context` option or `modules.localIdentContext` option.
|
|
- `[file]` - filename and path.
|
|
- `[ext]` - extension with leading `.`.
|
|
- `[hash]` - the hash of the string, generated based on `localIdentHashSalt`, `localIdentHashFunction`, `localIdentHashDigest`, `localIdentHashDigestLength`, `localIdentContext`, `resourcePath` and `exportName`
|
|
- `[<hashFunction>:hash:<hashDigest>:<hashDigestLength>]` - hash with hash settings.
|
|
- `[local]` - original class.
|
|
|
|
Recommendations:
|
|
|
|
- use `'[path][name]__[local]'` for development
|
|
- use `'[hash:base64]'` for production
|
|
|
|
The `[local]` placeholder contains original class.
|
|
|
|
**Note:** all reserved (`<>:"/\|?*`) and control filesystem characters (excluding characters in the `[local]` placeholder) will be converted to `-`.
|
|
|
|
**webpack.config.js**
|
|
|
|
```js
|
|
module.exports = {
|
|
module: {
|
|
rules: [
|
|
{
|
|
test: /\.css$/i,
|
|
loader: "css-loader",
|
|
options: {
|
|
modules: {
|
|
localIdentName: "[path][name]__[local]--[hash:base64:5]",
|
|
},
|
|
},
|
|
},
|
|
],
|
|
},
|
|
};
|
|
```
|
|
|
|
##### `localIdentContext`
|
|
|
|
Type:
|
|
|
|
```ts
|
|
type localIdentContex = string;
|
|
```
|
|
|
|
Default: `compiler.context`
|
|
|
|
Allows to redefine basic loader context for local ident name.
|
|
|
|
**webpack.config.js**
|
|
|
|
```js
|
|
module.exports = {
|
|
module: {
|
|
rules: [
|
|
{
|
|
test: /\.css$/i,
|
|
loader: "css-loader",
|
|
options: {
|
|
modules: {
|
|
localIdentContext: path.resolve(__dirname, "src"),
|
|
},
|
|
},
|
|
},
|
|
],
|
|
},
|
|
};
|
|
```
|
|
|
|
##### `localIdentHashSalt`
|
|
|
|
Type:
|
|
|
|
```ts
|
|
type localIdentHashSalt = string;
|
|
```
|
|
|
|
Default: `undefined`
|
|
|
|
Allows to add custom hash to generate more unique classes.
|
|
For more information see [output.hashSalt](https://webpack.js.org/configuration/output/#outputhashsalt).
|
|
|
|
**webpack.config.js**
|
|
|
|
```js
|
|
module.exports = {
|
|
module: {
|
|
rules: [
|
|
{
|
|
test: /\.css$/i,
|
|
loader: "css-loader",
|
|
options: {
|
|
modules: {
|
|
localIdentHashSalt: "hash",
|
|
},
|
|
},
|
|
},
|
|
],
|
|
},
|
|
};
|
|
```
|
|
|
|
##### `localIdentHashFunction`
|
|
|
|
Type:
|
|
|
|
```ts
|
|
type localIdentHashFunction = string;
|
|
```
|
|
|
|
Default: `md4`
|
|
|
|
Allows to specify hash function to generate classes .
|
|
For more information see [output.hashFunction](https://webpack.js.org/configuration/output/#outputhashfunction).
|
|
|
|
**webpack.config.js**
|
|
|
|
```js
|
|
module.exports = {
|
|
module: {
|
|
rules: [
|
|
{
|
|
test: /\.css$/i,
|
|
loader: "css-loader",
|
|
options: {
|
|
modules: {
|
|
localIdentHashFunction: "md4",
|
|
},
|
|
},
|
|
},
|
|
],
|
|
},
|
|
};
|
|
```
|
|
|
|
##### `localIdentHashDigest`
|
|
|
|
Type:
|
|
|
|
```ts
|
|
type localIdentHashDigest = string;
|
|
```
|
|
|
|
Default: `hex`
|
|
|
|
Allows to specify hash digest to generate classes.
|
|
For more information see [output.hashDigest](https://webpack.js.org/configuration/output/#outputhashdigest).
|
|
|
|
**webpack.config.js**
|
|
|
|
```js
|
|
module.exports = {
|
|
module: {
|
|
rules: [
|
|
{
|
|
test: /\.css$/i,
|
|
loader: "css-loader",
|
|
options: {
|
|
modules: {
|
|
localIdentHashDigest: "base64",
|
|
},
|
|
},
|
|
},
|
|
],
|
|
},
|
|
};
|
|
```
|
|
|
|
##### `localIdentHashDigestLength`
|
|
|
|
Type:
|
|
|
|
```ts
|
|
type localIdentHashDigestLength = number;
|
|
```
|
|
|
|
Default: `20`
|
|
|
|
Allows to specify hash digest length to generate classes.
|
|
For more information see [output.hashDigestLength](https://webpack.js.org/configuration/output/#outputhashdigestlength).
|
|
|
|
**webpack.config.js**
|
|
|
|
```js
|
|
module.exports = {
|
|
module: {
|
|
rules: [
|
|
{
|
|
test: /\.css$/i,
|
|
loader: "css-loader",
|
|
options: {
|
|
modules: {
|
|
localIdentHashDigestLength: 5,
|
|
},
|
|
},
|
|
},
|
|
],
|
|
},
|
|
};
|
|
```
|
|
|
|
##### `hashStrategy`
|
|
|
|
Type: `'resource-path-and-local-name' | 'minimal-subset'`
|
|
Default: `'resource-path-and-local-name'`
|
|
|
|
Should local name be used when computing the hash.
|
|
|
|
- `'resource-path-and-local-name'` Both resource path and local name are used when hashing. Each identifier in a module gets its own hash digest, always.
|
|
- `'minimal-subset'` Auto detect if identifier names can be omitted from hashing. Use this value to optimize the output for better GZIP or Brotli compression.
|
|
|
|
**webpack.config.js**
|
|
|
|
```js
|
|
module.exports = {
|
|
module: {
|
|
rules: [
|
|
{
|
|
test: /\.css$/i,
|
|
loader: "css-loader",
|
|
options: {
|
|
modules: {
|
|
hashStrategy: "minimal-subset",
|
|
},
|
|
},
|
|
},
|
|
],
|
|
},
|
|
};
|
|
```
|
|
|
|
##### `localIdentRegExp`
|
|
|
|
Type:
|
|
|
|
```ts
|
|
type localIdentRegExp = string | RegExp;
|
|
```
|
|
|
|
Default: `undefined`
|
|
|
|
**webpack.config.js**
|
|
|
|
```js
|
|
module.exports = {
|
|
module: {
|
|
rules: [
|
|
{
|
|
test: /\.css$/i,
|
|
loader: "css-loader",
|
|
options: {
|
|
modules: {
|
|
localIdentRegExp: /page-(.*)\.css/i,
|
|
},
|
|
},
|
|
},
|
|
],
|
|
},
|
|
};
|
|
```
|
|
|
|
##### `getLocalIdent`
|
|
|
|
Type:
|
|
|
|
```ts
|
|
type getLocalIdent = (
|
|
context: LoaderContext,
|
|
localIdentName: string,
|
|
localName: string
|
|
) => string;
|
|
```
|
|
|
|
Default: `undefined`
|
|
|
|
Allows to specify a function to generate the classname.
|
|
By default we use built-in function to generate a classname.
|
|
If the custom function returns `null` or `undefined`, we fallback to the
|
|
built-in function to generate the classname.
|
|
|
|
**webpack.config.js**
|
|
|
|
```js
|
|
module.exports = {
|
|
module: {
|
|
rules: [
|
|
{
|
|
test: /\.css$/i,
|
|
loader: "css-loader",
|
|
options: {
|
|
modules: {
|
|
getLocalIdent: (context, localIdentName, localName, options) => {
|
|
return "whatever_random_class_name";
|
|
},
|
|
},
|
|
},
|
|
},
|
|
],
|
|
},
|
|
};
|
|
```
|
|
|
|
##### `namedExport`
|
|
|
|
Type:
|
|
|
|
```ts
|
|
type namedExport = boolean;
|
|
```
|
|
|
|
Default: `false`
|
|
|
|
Enables/disables ES modules named export for locals.
|
|
|
|
> **Warning**
|
|
>
|
|
> Names of locals are converted to camelcase, i.e. the `exportLocalsConvention` option has `camelCaseOnly` value by default.
|
|
|
|
> **Warning**
|
|
>
|
|
> It is not allowed to use JavaScript reserved words in css class names.
|
|
|
|
**styles.css**
|
|
|
|
```css
|
|
.foo-baz {
|
|
color: red;
|
|
}
|
|
.bar {
|
|
color: blue;
|
|
}
|
|
```
|
|
|
|
**index.js**
|
|
|
|
```js
|
|
import { fooBaz, bar } from "./styles.css";
|
|
|
|
console.log(fooBaz, bar);
|
|
```
|
|
|
|
You can enable a ES module named export using:
|
|
|
|
**webpack.config.js**
|
|
|
|
```js
|
|
module.exports = {
|
|
module: {
|
|
rules: [
|
|
{
|
|
test: /\.css$/i,
|
|
loader: "css-loader",
|
|
options: {
|
|
esModule: true,
|
|
modules: {
|
|
namedExport: true,
|
|
},
|
|
},
|
|
},
|
|
],
|
|
},
|
|
};
|
|
```
|
|
|
|
To set a custom name for namedExport, can use [`exportLocalsConvention`](#exportLocalsConvention) option as a function.
|
|
Example below in the [`examples`](#examples) section.
|
|
|
|
##### `exportGlobals`
|
|
|
|
Type:
|
|
|
|
```ts
|
|
type exportsGLobals = boolean;
|
|
```
|
|
|
|
Default: `false`
|
|
|
|
Allow `css-loader` to export names from global class or id, so you can use that as local name.
|
|
|
|
**webpack.config.js**
|
|
|
|
```js
|
|
module.exports = {
|
|
module: {
|
|
rules: [
|
|
{
|
|
test: /\.css$/i,
|
|
loader: "css-loader",
|
|
options: {
|
|
modules: {
|
|
exportGlobals: true,
|
|
},
|
|
},
|
|
},
|
|
],
|
|
},
|
|
};
|
|
```
|
|
|
|
##### `exportLocalsConvention`
|
|
|
|
Type:
|
|
|
|
```ts
|
|
type exportLocalsConvention =
|
|
| "asIs"
|
|
| "camelCase"
|
|
| "camelCaseOnly"
|
|
| "dashes"
|
|
| "dashesOnly"
|
|
| ((name: string) => string);
|
|
```
|
|
|
|
Default: based on the `modules.namedExport` option value, if `true` - `camelCaseOnly`, otherwise `asIs`
|
|
|
|
Style of exported class names.
|
|
|
|
###### `string`
|
|
|
|
By default, the exported JSON keys mirror the class names (i.e `asIs` value).
|
|
|
|
> **Warning**
|
|
>
|
|
> Only `camelCaseOnly` value allowed if you set the `namedExport` value to `true`.
|
|
|
|
| Name | Type | Description |
|
|
| :-------------------: | :------: | :----------------------------------------------------------------------------------------------- |
|
|
| **`'asIs'`** | `string` | Class names will be exported as is. |
|
|
| **`'camelCase'`** | `string` | Class names will be camelized, the original class name will not to be removed from the locals |
|
|
| **`'camelCaseOnly'`** | `string` | Class names will be camelized, the original class name will be removed from the locals |
|
|
| **`'dashes'`** | `string` | Only dashes in class names will be camelized |
|
|
| **`'dashesOnly'`** | `string` | Dashes in class names will be camelized, the original class name will be removed from the locals |
|
|
|
|
**file.css**
|
|
|
|
```css
|
|
.class-name {
|
|
}
|
|
```
|
|
|
|
**file.js**
|
|
|
|
```js
|
|
import { className } from "file.css";
|
|
```
|
|
|
|
**webpack.config.js**
|
|
|
|
```js
|
|
module.exports = {
|
|
module: {
|
|
rules: [
|
|
{
|
|
test: /\.css$/i,
|
|
loader: "css-loader",
|
|
options: {
|
|
modules: {
|
|
exportLocalsConvention: "camelCase",
|
|
},
|
|
},
|
|
},
|
|
],
|
|
},
|
|
};
|
|
```
|
|
|
|
###### `function`
|
|
|
|
**webpack.config.js**
|
|
|
|
```js
|
|
module.exports = {
|
|
module: {
|
|
rules: [
|
|
{
|
|
test: /\.css$/i,
|
|
loader: "css-loader",
|
|
options: {
|
|
modules: {
|
|
exportLocalsConvention: function (name) {
|
|
return name.replace(/-/g, "_");
|
|
},
|
|
},
|
|
},
|
|
},
|
|
],
|
|
},
|
|
};
|
|
```
|
|
|
|
**webpack.config.js**
|
|
|
|
```js
|
|
module.exports = {
|
|
module: {
|
|
rules: [
|
|
{
|
|
test: /\.css$/i,
|
|
loader: "css-loader",
|
|
options: {
|
|
modules: {
|
|
exportLocalsConvention: function (name) {
|
|
return [
|
|
name.replace(/-/g, "_"),
|
|
// dashesCamelCase
|
|
name.replace(/-+(\w)/g, (match, firstLetter) =>
|
|
firstLetter.toUpperCase()
|
|
),
|
|
];
|
|
},
|
|
},
|
|
},
|
|
},
|
|
],
|
|
},
|
|
};
|
|
```
|
|
|
|
##### `exportOnlyLocals`
|
|
|
|
Type:
|
|
|
|
```ts
|
|
type exportOnlyLocals = boolean;
|
|
```
|
|
|
|
Default: `false`
|
|
|
|
Export only locals.
|
|
|
|
**Useful** when you use **css modules** for pre-rendering (for example SSR).
|
|
For pre-rendering with `mini-css-extract-plugin` you should use this option instead of `style-loader!css-loader` **in the pre-rendering bundle**.
|
|
It doesn't embed CSS but only exports the identifier mappings.
|
|
|
|
**webpack.config.js**
|
|
|
|
```js
|
|
module.exports = {
|
|
module: {
|
|
rules: [
|
|
{
|
|
test: /\.css$/i,
|
|
loader: "css-loader",
|
|
options: {
|
|
modules: {
|
|
exportOnlyLocals: true,
|
|
},
|
|
},
|
|
},
|
|
],
|
|
},
|
|
};
|
|
```
|
|
|
|
### `importLoaders`
|
|
|
|
Type:
|
|
|
|
```ts
|
|
type importLoaders = number;
|
|
```
|
|
|
|
Default: `0`
|
|
|
|
Allows to enables/disables or setups number of loaders applied before CSS loader for `@import` at-rules, CSS modules and ICSS imports, i.e. `@import`/`composes`/`@value value from './values.css'`/etc.
|
|
|
|
The option `importLoaders` allows you to configure how many loaders before `css-loader` should be applied to `@import`ed resources and CSS modules/ICSS imports.
|
|
|
|
**webpack.config.js**
|
|
|
|
```js
|
|
module.exports = {
|
|
module: {
|
|
rules: [
|
|
{
|
|
test: /\.css$/i,
|
|
use: [
|
|
"style-loader",
|
|
{
|
|
loader: "css-loader",
|
|
options: {
|
|
importLoaders: 2,
|
|
// 0 => no loaders (default);
|
|
// 1 => postcss-loader;
|
|
// 2 => postcss-loader, sass-loader
|
|
},
|
|
},
|
|
"postcss-loader",
|
|
"sass-loader",
|
|
],
|
|
},
|
|
],
|
|
},
|
|
};
|
|
```
|
|
|
|
This may change in the future when the module system (i. e. webpack) supports loader matching by origin.
|
|
|
|
### `sourceMap`
|
|
|
|
Type:
|
|
|
|
```ts
|
|
type sourceMap = boolean;
|
|
```
|
|
|
|
Default: depends on the `compiler.devtool` value
|
|
|
|
By default generation of source maps depends on the [`devtool`](https://webpack.js.org/configuration/devtool/) option. All values enable source map generation except `eval` and `false` value.
|
|
|
|
**webpack.config.js**
|
|
|
|
```js
|
|
module.exports = {
|
|
module: {
|
|
rules: [
|
|
{
|
|
test: /\.css$/i,
|
|
loader: "css-loader",
|
|
options: {
|
|
sourceMap: true,
|
|
},
|
|
},
|
|
],
|
|
},
|
|
};
|
|
```
|
|
|
|
### `esModule`
|
|
|
|
Type:
|
|
|
|
```ts
|
|
type esModule = boolean;
|
|
```
|
|
|
|
Default: `true`
|
|
|
|
By default, `css-loader` 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](https://webpack.js.org/plugins/module-concatenation-plugin/) and [tree shaking](https://webpack.js.org/guides/tree-shaking/).
|
|
|
|
You can enable a CommonJS modules syntax using:
|
|
|
|
**webpack.config.js**
|
|
|
|
```js
|
|
module.exports = {
|
|
module: {
|
|
rules: [
|
|
{
|
|
test: /\.css$/i,
|
|
loader: "css-loader",
|
|
options: {
|
|
esModule: false,
|
|
},
|
|
},
|
|
],
|
|
},
|
|
};
|
|
```
|
|
|
|
### `exportType`
|
|
|
|
Type:
|
|
|
|
```ts
|
|
type exportType = "array" | "string" | "css-style-sheet";
|
|
```
|
|
|
|
Default: `'array'`
|
|
|
|
Allows exporting styles as array with modules, string or [constructable stylesheet](https://developers.google.com/web/updates/2019/02/constructable-stylesheets) (i.e. [`CSSStyleSheet`](https://developer.mozilla.org/en-US/docs/Web/API/CSSStyleSheet)).
|
|
Default value is `'array'`, i.e. loader exports array of modules with specific API which is used in `style-loader` or other.
|
|
|
|
**webpack.config.js**
|
|
|
|
```js
|
|
module.exports = {
|
|
module: {
|
|
rules: [
|
|
{
|
|
assert: { type: "css" },
|
|
loader: "css-loader",
|
|
options: {
|
|
exportType: "css-style-sheet",
|
|
},
|
|
},
|
|
],
|
|
},
|
|
};
|
|
```
|
|
|
|
**src/index.js**
|
|
|
|
```js
|
|
import sheet from "./styles.css" assert { type: "css" };
|
|
|
|
document.adoptedStyleSheets = [sheet];
|
|
shadowRoot.adoptedStyleSheets = [sheet];
|
|
```
|
|
|
|
#### `'array'`
|
|
|
|
The default export is array of modules with specific API which is used in `style-loader` or other.
|
|
|
|
**webpack.config.js**
|
|
|
|
```js
|
|
module.exports = {
|
|
module: {
|
|
rules: [
|
|
{
|
|
test: /\.(sa|sc|c)ss$/i,
|
|
use: ["style-loader", "css-loader", "postcss-loader", "sass-loader"],
|
|
},
|
|
],
|
|
},
|
|
};
|
|
```
|
|
|
|
**src/index.js**
|
|
|
|
```js
|
|
// `style-loader` applies styles to DOM
|
|
import "./styles.css";
|
|
```
|
|
|
|
#### `'string'`
|
|
|
|
> **Warning**
|
|
>
|
|
> You don't need [`style-loader`](https://github.com/webpack-contrib/style-loader) anymore, please remove it.
|
|
|
|
> **Warning**
|
|
>
|
|
> The `esModules` option should be enabled if you want to use it with [`CSS modules`](https://github.com/webpack-contrib/css-loader#modules), by default for locals will be used [named export](https://github.com/webpack-contrib/css-loader#namedexport).
|
|
|
|
The default export is `string`.
|
|
|
|
**webpack.config.js**
|
|
|
|
```js
|
|
module.exports = {
|
|
module: {
|
|
rules: [
|
|
{
|
|
test: /\.(sa|sc|c)ss$/i,
|
|
use: ["css-loader", "postcss-loader", "sass-loader"],
|
|
},
|
|
],
|
|
},
|
|
};
|
|
```
|
|
|
|
**src/index.js**
|
|
|
|
```js
|
|
import sheet from "./styles.css";
|
|
|
|
console.log(sheet);
|
|
```
|
|
|
|
#### `'css-style-sheet'`
|
|
|
|
> **Warning**
|
|
>
|
|
> `@import` rules not yet allowed, more [information](https://web.dev/css-module-scripts/#@import-rules-not-yet-allowed)
|
|
|
|
> **Warning**
|
|
>
|
|
> You don't need [`style-loader`](https://github.com/webpack-contrib/style-loader) anymore, please remove it.
|
|
|
|
> **Warning**
|
|
>
|
|
> The `esModules` option should be enabled if you want to use it with [`CSS modules`](https://github.com/webpack-contrib/css-loader#modules), by default for locals will be used [named export](https://github.com/webpack-contrib/css-loader#namedexport).
|
|
|
|
> **Warning**
|
|
>
|
|
> Source maps are not currently supported in `Chrome` due [bug](https://bugs.chromium.org/p/chromium/issues/detail?id=1174094&q=CSSStyleSheet%20source%20maps&can=2)
|
|
|
|
The default export is a [constructable stylesheet](https://developers.google.com/web/updates/2019/02/constructable-stylesheets) (i.e. [`CSSStyleSheet`](https://developer.mozilla.org/en-US/docs/Web/API/CSSStyleSheet)).
|
|
|
|
Useful for [custom elements](https://developer.mozilla.org/en-US/docs/Web/Web_Components/Using_custom_elements) and shadow DOM.
|
|
|
|
More information:
|
|
|
|
- [Using CSS Module Scripts to import stylesheets](https://web.dev/css-module-scripts/)
|
|
- [Constructable Stylesheets: seamless reusable styles](https://developers.google.com/web/updates/2019/02/constructable-stylesheets)
|
|
|
|
**webpack.config.js**
|
|
|
|
```js
|
|
module.exports = {
|
|
module: {
|
|
rules: [
|
|
{
|
|
assert: { type: "css" },
|
|
loader: "css-loader",
|
|
options: {
|
|
exportType: "css-style-sheet",
|
|
},
|
|
},
|
|
|
|
// For Sass/SCSS:
|
|
//
|
|
// {
|
|
// assert: { type: "css" },
|
|
// rules: [
|
|
// {
|
|
// loader: "css-loader",
|
|
// options: {
|
|
// exportType: "css-style-sheet",
|
|
// // Other options
|
|
// },
|
|
// },
|
|
// {
|
|
// loader: "sass-loader",
|
|
// options: {
|
|
// // Other options
|
|
// },
|
|
// },
|
|
// ],
|
|
// },
|
|
],
|
|
},
|
|
};
|
|
```
|
|
|
|
**src/index.js**
|
|
|
|
```js
|
|
// Example for Sass/SCSS:
|
|
// import sheet from "./styles.scss" assert { type: "css" };
|
|
|
|
// Example for CSS modules:
|
|
// import sheet, { myClass } from "./styles.scss" assert { type: "css" };
|
|
|
|
// Example for CSS:
|
|
import sheet from "./styles.css" assert { type: "css" };
|
|
|
|
document.adoptedStyleSheets = [sheet];
|
|
shadowRoot.adoptedStyleSheets = [sheet];
|
|
```
|
|
|
|
For migration purposes, you can use the following configuration:
|
|
|
|
```js
|
|
module.exports = {
|
|
module: {
|
|
rules: [
|
|
{
|
|
test: /\.css$/i,
|
|
oneOf: [
|
|
{
|
|
assert: { type: "css" },
|
|
loader: "css-loader",
|
|
options: {
|
|
exportType: "css-style-sheet",
|
|
// Other options
|
|
},
|
|
},
|
|
{
|
|
use: [
|
|
"style-loader",
|
|
{
|
|
loader: "css-loader",
|
|
options: {
|
|
// Other options
|
|
},
|
|
},
|
|
],
|
|
},
|
|
],
|
|
},
|
|
],
|
|
},
|
|
};
|
|
```
|
|
|
|
## 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](https://github.com/webpack-contrib/mini-css-extract-plugin), because it creates separate css files.
|
|
For `development` mode (including `webpack-dev-server`) you can use [style-loader](https://github.com/webpack-contrib/style-loader), because it injects CSS into the DOM using multiple <style></style> and works faster.
|
|
|
|
> **Note**
|
|
>
|
|
> Do not use `style-loader` and `mini-css-extract-plugin` together.
|
|
|
|
**webpack.config.js**
|
|
|
|
```js
|
|
const MiniCssExtractPlugin = require("mini-css-extract-plugin");
|
|
const devMode = process.env.NODE_ENV !== "production";
|
|
|
|
module.exports = {
|
|
module: {
|
|
rules: [
|
|
{
|
|
// If you enable `experiments.css` or `experiments.futureDefaults`, please uncomment line below
|
|
// type: "javascript/auto",
|
|
test: /\.(sa|sc|c)ss$/i,
|
|
use: [
|
|
devMode ? "style-loader" : MiniCssExtractPlugin.loader,
|
|
"css-loader",
|
|
"postcss-loader",
|
|
"sass-loader",
|
|
],
|
|
},
|
|
],
|
|
},
|
|
plugins: [].concat(devMode ? [] : [new MiniCssExtractPlugin()]),
|
|
};
|
|
```
|
|
|
|
### Disable url resolving using the `/* webpackIgnore: true */` comment
|
|
|
|
With the help of the `/* webpackIgnore: true */`comment, it is possible to disable sources handling for rules and for individual declarations.
|
|
|
|
```css
|
|
/* webpackIgnore: true */
|
|
@import url(./basic.css);
|
|
@import /* webpackIgnore: true */ url(./imported.css);
|
|
|
|
.class {
|
|
/* Disabled url handling for the all urls in the 'background' declaration */
|
|
color: red;
|
|
/* webpackIgnore: true */
|
|
background: url("./url/img.png"), url("./url/img.png");
|
|
}
|
|
|
|
.class {
|
|
/* Disabled url handling for the first url in the 'background' declaration */
|
|
color: red;
|
|
background:
|
|
/* webpackIgnore: true */ url("./url/img.png"), url("./url/img.png");
|
|
}
|
|
|
|
.class {
|
|
/* Disabled url handling for the second url in the 'background' declaration */
|
|
color: red;
|
|
background: url("./url/img.png"),
|
|
/* webpackIgnore: true */ url("./url/img.png");
|
|
}
|
|
|
|
/* prettier-ignore */
|
|
.class {
|
|
/* Disabled url handling for the second url in the 'background' declaration */
|
|
color: red;
|
|
background: url("./url/img.png"),
|
|
/* webpackIgnore: true */
|
|
url("./url/img.png");
|
|
}
|
|
|
|
/* prettier-ignore */
|
|
.class {
|
|
/* Disabled url handling for third and sixth urls in the 'background-image' declaration */
|
|
background-image: image-set(
|
|
url(./url/img.png) 2x,
|
|
url(./url/img.png) 3x,
|
|
/* webpackIgnore: true */ url(./url/img.png) 4x,
|
|
url(./url/img.png) 5x,
|
|
url(./url/img.png) 6x,
|
|
/* webpackIgnore: true */
|
|
url(./url/img.png) 7x
|
|
);
|
|
}
|
|
```
|
|
|
|
### Assets
|
|
|
|
The following `webpack.config.js` can load CSS files, embed small PNG/JPG/GIF/SVG images as well as fonts as [Data URLs](https://tools.ietf.org/html/rfc2397) and copy larger files to the output directory.
|
|
|
|
**For webpack v5:**
|
|
|
|
**webpack.config.js**
|
|
|
|
```js
|
|
module.exports = {
|
|
module: {
|
|
rules: [
|
|
{
|
|
test: /\.css$/i,
|
|
use: ["style-loader", "css-loader"],
|
|
},
|
|
{
|
|
test: /\.(png|jpe?g|gif|svg|eot|ttf|woff|woff2)$/i,
|
|
// More information here https://webpack.js.org/guides/asset-modules/
|
|
type: "asset",
|
|
},
|
|
],
|
|
},
|
|
};
|
|
```
|
|
|
|
### Extract
|
|
|
|
For production builds it's recommended to extract the CSS from your bundle being able to use parallel loading of CSS/JS resources later on.
|
|
|
|
- This can be achieved by using the [mini-css-extract-plugin](https://github.com/webpack-contrib/mini-css-extract-plugin) to extract the CSS when running in production mode.
|
|
|
|
- As an alternative, if seeking better development performance and css outputs that mimic production. [extract-css-chunks-webpack-plugin](https://github.com/faceyspacey/extract-css-chunks-webpack-plugin) offers a hot module reload friendly, extended version of mini-css-extract-plugin. HMR real CSS files in dev, works like mini-css in non-dev
|
|
|
|
### Pure CSS, CSS modules and PostCSS
|
|
|
|
When you have pure CSS (without CSS modules), CSS modules and PostCSS in your project you can use this setup:
|
|
|
|
**webpack.config.js**
|
|
|
|
```js
|
|
module.exports = {
|
|
module: {
|
|
rules: [
|
|
{
|
|
// For pure CSS - /\.css$/i,
|
|
// For Sass/SCSS - /\.((c|sa|sc)ss)$/i,
|
|
// For Less - /\.((c|le)ss)$/i,
|
|
test: /\.((c|sa|sc)ss)$/i,
|
|
use: [
|
|
"style-loader",
|
|
{
|
|
loader: "css-loader",
|
|
options: {
|
|
// Run `postcss-loader` on each CSS `@import` and CSS modules/ICSS imports, do not forget that `sass-loader` compile non CSS `@import`'s into a single file
|
|
// If you need run `sass-loader` and `postcss-loader` on each CSS `@import` please set it to `2`
|
|
importLoaders: 1,
|
|
},
|
|
},
|
|
{
|
|
loader: "postcss-loader",
|
|
options: { plugins: () => [postcssPresetEnv({ stage: 0 })] },
|
|
},
|
|
// Can be `less-loader`
|
|
{
|
|
loader: "sass-loader",
|
|
},
|
|
],
|
|
},
|
|
// For webpack v5
|
|
{
|
|
test: /\.(png|jpe?g|gif|svg|eot|ttf|woff|woff2)$/i,
|
|
// More information here https://webpack.js.org/guides/asset-modules/
|
|
type: "asset",
|
|
},
|
|
],
|
|
},
|
|
};
|
|
```
|
|
|
|
### Resolve unresolved URLs using an alias
|
|
|
|
**index.css**
|
|
|
|
```css
|
|
.class {
|
|
background: url(/assets/unresolved/img.png);
|
|
}
|
|
```
|
|
|
|
**webpack.config.js**
|
|
|
|
```js
|
|
module.exports = {
|
|
module: {
|
|
rules: [
|
|
{
|
|
test: /\.css$/i,
|
|
use: ["style-loader", "css-loader"],
|
|
},
|
|
],
|
|
},
|
|
resolve: {
|
|
alias: {
|
|
"/assets/unresolved/img.png": path.resolve(
|
|
__dirname,
|
|
"assets/real-path-to-img/img.png"
|
|
),
|
|
},
|
|
},
|
|
};
|
|
```
|
|
|
|
### Named export with custom export names
|
|
|
|
**webpack.config.js**
|
|
|
|
```js
|
|
module.exports = {
|
|
module: {
|
|
rules: [
|
|
{
|
|
test: /\.css$/i,
|
|
loader: "css-loader",
|
|
options: {
|
|
modules: {
|
|
namedExport: true,
|
|
exportLocalsConvention: function (name) {
|
|
return name.replace(/-/g, "_");
|
|
},
|
|
},
|
|
},
|
|
},
|
|
],
|
|
},
|
|
};
|
|
```
|
|
|
|
### Separating `Interoperable CSS`-only and `CSS Module` features
|
|
|
|
The following setup is an example of allowing `Interoperable CSS` features only (such as `:import` and `:export`) without using further `CSS Module` functionality by setting `mode` option for all files that do not match `*.module.scss` naming convention. This is for reference as having `ICSS` features applied to all files was default `css-loader` behavior before v4.
|
|
Meanwhile all files matching `*.module.scss` are treated as `CSS Modules` in this example.
|
|
|
|
An example case is assumed where a project requires canvas drawing variables to be synchronized with CSS - canvas drawing uses the same color (set by color name in JavaScript) as HTML background (set by class name in CSS).
|
|
|
|
**webpack.config.js**
|
|
|
|
```js
|
|
module.exports = {
|
|
module: {
|
|
rules: [
|
|
// ...
|
|
// --------
|
|
// SCSS ALL EXCEPT MODULES
|
|
{
|
|
test: /\.scss$/i,
|
|
exclude: /\.module\.scss$/i,
|
|
use: [
|
|
{
|
|
loader: "style-loader",
|
|
},
|
|
{
|
|
loader: "css-loader",
|
|
options: {
|
|
importLoaders: 1,
|
|
modules: {
|
|
mode: "icss",
|
|
},
|
|
},
|
|
},
|
|
{
|
|
loader: "sass-loader",
|
|
},
|
|
],
|
|
},
|
|
// --------
|
|
// SCSS MODULES
|
|
{
|
|
test: /\.module\.scss$/i,
|
|
use: [
|
|
{
|
|
loader: "style-loader",
|
|
},
|
|
{
|
|
loader: "css-loader",
|
|
options: {
|
|
importLoaders: 1,
|
|
modules: {
|
|
mode: "local",
|
|
},
|
|
},
|
|
},
|
|
{
|
|
loader: "sass-loader",
|
|
},
|
|
],
|
|
},
|
|
// --------
|
|
// ...
|
|
],
|
|
},
|
|
};
|
|
```
|
|
|
|
**variables.scss**
|
|
|
|
File treated as `ICSS`-only.
|
|
|
|
```scss
|
|
$colorBackground: red;
|
|
:export {
|
|
colorBackgroundCanvas: $colorBackground;
|
|
}
|
|
```
|
|
|
|
**Component.module.scss**
|
|
|
|
File treated as `CSS Module`.
|
|
|
|
```scss
|
|
@import "variables.scss";
|
|
.componentClass {
|
|
background-color: $colorBackground;
|
|
}
|
|
```
|
|
|
|
**Component.jsx**
|
|
|
|
Using both `CSS Module` functionality as well as SCSS variables directly in JavaScript.
|
|
|
|
```jsx
|
|
import svars from "variables.scss";
|
|
import styles from "Component.module.scss";
|
|
|
|
// Render DOM with CSS modules class name
|
|
// <div className={styles.componentClass}>
|
|
// <canvas ref={mountsCanvas}/>
|
|
// </div>
|
|
|
|
// Somewhere in JavaScript canvas drawing code use the variable directly
|
|
// const ctx = mountsCanvas.current.getContext('2d',{alpha: false});
|
|
ctx.fillStyle = `${svars.colorBackgroundCanvas}`;
|
|
```
|
|
|
|
## Contributing
|
|
|
|
Please take a moment to read our contributing guidelines if you haven't yet done so.
|
|
|
|
[CONTRIBUTING](./.github/CONTRIBUTING.md)
|
|
|
|
## License
|
|
|
|
[MIT](./LICENSE)
|
|
|
|
[npm]: https://img.shields.io/npm/v/css-loader.svg
|
|
[npm-url]: https://npmjs.com/package/css-loader
|
|
[node]: https://img.shields.io/node/v/css-loader.svg
|
|
[node-url]: https://nodejs.org
|
|
[tests]: https://github.com/webpack-contrib/css-loader/workflows/css-loader/badge.svg
|
|
[tests-url]: https://github.com/webpack-contrib/css-loader/actions
|
|
[cover]: https://codecov.io/gh/webpack-contrib/css-loader/branch/master/graph/badge.svg
|
|
[cover-url]: https://codecov.io/gh/webpack-contrib/css-loader
|
|
[discussion]: https://img.shields.io/github/discussions/webpack/webpack
|
|
[discussion-url]: https://github.com/webpack/webpack/discussions
|
|
[size]: https://packagephobia.now.sh/badge?p=css-loader
|
|
[size-url]: https://packagephobia.now.sh/result?p=css-loader
|