467 lines
11 KiB
Markdown
467 lines
11 KiB
Markdown
[![npm][npm]][npm-url]
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[![node][node]][node-url]
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[![deps][deps]][deps-url]
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[![tests][tests]][tests-url]
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[![coverage][cover]][cover-url]
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[![chat][chat]][chat-url]
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<div align="center">
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<img width="180" height="180" hspace="10"
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alt="PostCSS Logo"
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src="http://postcss.github.io/postcss/logo.svg">
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<a href="https://github.com/webpack/webpack">
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<img width="200" height="200" hspace="10"
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src="https://cdn.rawgit.com/webpack/media/e7485eb2/logo/icon.svg">
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</a>
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<div align="center">
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<a href="https://evilmartians.com/?utm_source=postcss">
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<img src="https://evilmartians.com/badges/sponsored-by-evil-martians.svg"
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alt="Sponsored by Evil Martians" width="236" height="54" vspace="10">
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</a>
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</div>
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<h1>PostCSS Loader</h1>
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<p>Loader for <a href="http://webpack.js.org/">webpack</a> to process CSS with <a href="http://postcss.org/">PostCSS</a></p>
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</div>
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<h2 align="center">Install</h2>
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```bash
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npm i -D postcss-loader
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```
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<h2 align="center">Usage</h2>
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### `Configuration`
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**postcss.config.js**
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```js
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module.exports = {
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parser: 'sugarss',
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plugins: {
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'postcss-import': {},
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'postcss-cssnext': {},
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'cssnano': {}
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}
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}
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```
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You can read more about common PostCSS Config [here](https://github.com/michael-ciniawsky/postcss-load-config).
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### `Config Cascade`
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You can use different `postcss.config.js` files in different directories.
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Config lookup starts from `path.dirname(file)` and walks the file tree upwards until a config file is found.
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```
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|– components
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| |– component
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| | |– index.js
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| | |– index.png
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| | |– style.css (1)
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| | |– postcss.config.js (1)
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| |– component
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| | |– index.js
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| | |– image.png
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| | |– style.css (2)
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|
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|– postcss.config.js (1 && 2 (recommended))
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|– webpack.config.js
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|
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|– package.json
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```
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After setting up your `postcss.config.js`, add `postcss-loader` to your `webpack.config.js`. You can use it standalone or in conjunction with `css-loader` (recommended). Use it **after** `css-loader` and `style-loader`, but **before** other preprocessor loaders like e.g `sass|less|stylus-loader`, if you use any.
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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$/,
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use: [ 'style-loader', 'postcss-loader' ]
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}
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]
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}
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}
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```
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> ⚠️ When `postcss-loader` is used standalone (without `css-loader`) don't use `@import` in your CSS, since this can lead to quite bloated bundles
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**webpack.config.js (recommended)**
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```js
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module.exports = {
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module: {
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rules: [
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{
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test: /\.css$/,
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use: [
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'style-loader',
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{ loader: 'css-loader', options: { importLoaders: 1 } },
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'postcss-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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```
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<h2 align="center">Options</h2>
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|Name|Type|Default|Description|
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|:--:|:--:|:-----:|:----------|
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|[`exec`](#exec)|`{Boolean}`|`undefined`|Enable PostCSS Parser support in `CSS-in-JS`|
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|[`parser`](#syntaxes)|`{String\|Object}`|`undefined`|Set PostCSS Parser|
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|[`syntax`](#syntaxes)|`{String\|Object}`|`undefined`|Set PostCSS Syntax|
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|[`stringifier`](#syntaxes)|`{String\|Object}`|`undefined`|Set PostCSS Stringifier|
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|[`config`](#config)|`{Object}`|`undefined`|Set `postcss.config.js` config path && `ctx`|
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|[`plugins`](#plugins)|`{Array\|Function}`|`[]`|Set PostCSS Plugins|
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|[`sourceMap`](#sourcemap)|`{String\|Boolean}`|`false`|Enable Source Maps|
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### `Exec`
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If you use JS styles without the [`postcss-js`][postcss-js] parser, add the `exec` option.
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```js
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{
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test: /\.style.js$/,
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use: [
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'style-loader',
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{ loader: 'css-loader', options: { importLoaders: 1 } },
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{ loader: 'postcss-loader', options: { parser: 'sugarss', exec: true } }
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]
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}
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```
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### `Config`
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|Name|Type|Default|Description|
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|:--:|:--:|:-----:|:----------|
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|[`path`](#path)|`{String}`|`undefined`|PostCSS Config Path|
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|[`context`](#context)|`{Object}`|`undefined`|PostCSS Config Context|
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#### `Path`
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You can manually specify the path to search for your config (`postcss.config.js`) with the `config.path` option. This is needed if you store your config in a separate e.g `./config || ./.config` folder.
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> ⚠️ Otherwise it is **unnecessary** to set this option and is **not** recommended
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**webpack.config.js**
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```js
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{
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loader: 'postcss-loader',
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options: {
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config: {
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path: 'path/to/postcss.config.js'
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}
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}
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}
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```
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#### `Context (ctx)`
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|Name|Type|Default|Description|
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|:--:|:--:|:-----:|:----------|
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|`env`|`{String}`|`'development'`|`process.env.NODE_ENV`|
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|`file`|`{Object}`|`loader.resourcePath`|`extname`, `dirname`, `basename`|
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|`options`|`{Object}`|`{}`|Options|
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`postcss-loader` exposes context `ctx` to the config file, making your `postcss.config.js` dynamic, so can use it to do some real magic ✨
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**postcss.config.js**
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```js
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module.exports = ({ file, options, env }) => ({
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parser: file.extname === '.sss' ? 'sugarss' : false,
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plugins: {
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'postcss-import': { root: file.dirname },
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'postcss-cssnext': options.cssnext ? options.cssnext : false,
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'autoprefixer': env === 'production' ? options.autoprefixer : false,
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'cssnano': env === 'production' ? options.cssnano : false
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}
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})
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```
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**webpack.config.js**
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```js
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{
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loader: 'postcss-loader',
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options: {
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config: {
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ctx: {
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cssnext: {...options},
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cssnano: {...options},
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autoprefixer: {...options}
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}
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}
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}
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}
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```
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### `Plugins`
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**webpack.config.js**
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```js
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{
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loader: 'postcss-loader',
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options: {
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ident: 'postcss',
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plugins: (loader) => [
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require('postcss-import')({ root: loader.resourcePath }),
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require('postcss-cssnext')(),
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require('autoprefixer')(),
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require('cssnano')()
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]
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}
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}
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```
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> ⚠️ webpack requires an identifier (`ident`) in `options` when `{Function}/require` is used (Complex Options). The `ident` can be freely named as long as it is unique. It's recommended to name it (`ident: 'postcss'`)
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### `Syntaxes`
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|Name|Type|Default|Description|
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|:--:|:--:|:-----:|:----------|
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|[`parser`](#parser)|`{String\|Function}`|`undefined`|Custom PostCSS Parser|
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|[`syntax`](#syntax)|`{String\|Function}`|`undefined`|Custom PostCSS Syntax|
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|[`stringifier`](#stringifier)|`{String\|Function}`|`undefined`|Custom PostCSS Stringifier|
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#### `Parser`
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**webpack.config.js**
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```js
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{
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test: /\.sss$/,
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use: [
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...,
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{ loader: 'postcss-loader', options: { parser: 'sugarss' } }
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]
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}
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```
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#### `Syntax`
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**webpack.config.js**
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```js
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{
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test: /\.css$/,
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use: [
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...,
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{ loader: 'postcss-loader', options: { syntax: 'sugarss' } }
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]
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}
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```
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#### `Stringifier`
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**webpack.config.js**
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```js
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{
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test: /\.css$/,
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use: [
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...,
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{ loader: 'postcss-loader', options: { stringifier: 'midas' } }
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]
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}
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```
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### `SourceMap`
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Enables source map support, `postcss-loader` will use the previous source map given by other loaders and update it accordingly, if no previous loader is applied before `postcss-loader`, the loader will generate a source map for you.
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**webpack.config.js**
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```js
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{
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test: /\.css/,
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use: [
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{ loader: 'style-loader', options: { sourceMap: true } },
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{ loader: 'css-loader', options: { sourceMap: true } },
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{ loader: 'postcss-loader', options: { sourceMap: true } },
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{ loader: 'sass-loader', options: { sourceMap: true } }
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]
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}
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```
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#### `'inline'`
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You can set the `sourceMap: 'inline'` option to inline the source map
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within the CSS directly as an annotation comment.
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**webpack.config.js**
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```js
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{
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loader: 'postcss-loader',
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options: {
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sourceMap: 'inline'
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}
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}
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```
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```css
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.class { color: red; }
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/*# sourceMappingURL=data:application/json;base64, ... */
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```
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<h2 align="center">Examples</h2>
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### `Stylelint`
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**webpack.config.js**
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```js
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{
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test: /\.css$/,
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use: [
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'style-loader',
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'css-loader',
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{
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loader: 'postcss-loader',
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options: {
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ident: 'postcss',
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plugins: [
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require('postcss-import')(),
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require('stylelint')(),
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...,
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]
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}
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}
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]
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}
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```
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### `CSS Modules`
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This loader [cannot be used] with [CSS Modules] out of the box due
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to the way `css-loader` processes file imports. To make them work properly,
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either add the css-loader’s [`importLoaders`] option.
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**webpack.config.js**
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```js
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{
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test: /\.css$/,
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use: [
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'style-loader',
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{ loader: 'css-loader', options: { modules: true, importLoaders: 1 } },
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'postcss-loader'
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]
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}
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```
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or use [postcss-modules] instead of `css-loader`.
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[`importLoaders`]: https://github.com/webpack-contrib/css-loader#importloaders
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[cannot be used]: https://github.com/webpack/css-loader/issues/137
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[CSS Modules]: https://github.com/webpack/css-loader#css-modules
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[postcss-modules]: https://github.com/outpunk/postcss-modules
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### `CSS-in-JS`
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If you want to process styles written in JavaScript, use the [postcss-js] parser.
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[postcss-js]: https://github.com/postcss/postcss-js
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```js
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{
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test: /\.style.js$/,
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use: [
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'style-loader',
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{ loader: 'css-loader', options: { importLoaders: 2 } },
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{ loader: 'postcss-loader', options: { parser: 'postcss-js' } },
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'babel-loader'
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]
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}
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```
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As result you will be able to write styles in the following way
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```js
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import colors from './styles/colors'
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export default {
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'.menu': {
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color: colors.main,
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height: 25,
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'&_link': {
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color: 'white'
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}
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}
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}
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```
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> :warning: If you are using Babel you need to do the following in order for the setup to work
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> 1. Add [babel-plugin-add-module-exports] to your configuration
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> 2. You need to have only one **default** export per style module
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[babel-plugin-add-module-exports]: https://github.com/59naga/babel-plugin-add-module-exports
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### [Extract CSS][ExtractPlugin]
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[ExtractPlugin]: https://github.com/webpack-contrib/extract-text-webpack-plugin
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**webpack.config.js**
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```js
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const ExtractTextPlugin = require('extract-text-webpack-plugin')
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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$/,
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use: ExtractTextPlugin.extract({
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fallback: 'style-loader',
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use: [
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{ loader: 'css-loader', options: { importLoaders: 1 } },
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'postcss-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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plugins: [
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new ExtractTextPlugin('[name].css')
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]
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}
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```
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<h2 align="center">Maintainers</h2>
|
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<table>
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<tbody>
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<tr>
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<td align="center">
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<a href="https://github.com/michael-ciniawsky">
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<img width="150" height="150" src="https://github.com/michael-ciniawsky.png?v=3&s=150">
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</br>
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Michael Ciniawsky
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</a>
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</td>
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<td align="center">
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<a href="https://github.com/evilebottnawi">
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<img width="150" height="150" src="https://github.com/evilebottnawi.png?v=3&s=150">
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</br>
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Alexander Krasnoyarov
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</a>
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</td>
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</tr>
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<tbody>
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</table>
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[npm]: https://img.shields.io/npm/v/postcss-loader.svg
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[npm-url]: https://npmjs.com/package/postcss-loader
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[node]: https://img.shields.io/node/v/postcss-loader.svg
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[node-url]: https://nodejs.org
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[deps]: https://david-dm.org/postcss/postcss-loader.svg
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[deps-url]: https://david-dm.org/postcss/postcss-loader
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[tests]: http://img.shields.io/travis/postcss/postcss-loader.svg
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[tests-url]: https://travis-ci.org/postcss/postcss-loader
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[cover]: https://coveralls.io/repos/github/postcss/postcss-loader/badge.svg
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[cover-url]: https://coveralls.io/github/postcss/postcss-loader
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|
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[chat]: https://badges.gitter.im/postcss/postcss.svg
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[chat-url]: https://gitter.im/postcss/postcss
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