You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
parttimejob/node_modules/postcss-loader/README.md

1102 lines
24 KiB

This file contains ambiguous Unicode characters!

This file contains ambiguous Unicode characters that may be confused with others in your current locale. If your use case is intentional and legitimate, you can safely ignore this warning. Use the Escape button to highlight these characters.

<div align="center">
<img
width="180"
height="180"
hspace="10"
alt="PostCSS Logo"
src="https://api.postcss.org/logo.svg">
<a href="https://github.com/webpack/webpack">
<img
width="200"
height="200"
hspace="10"
src="https://cdn.rawgit.com/webpack/media/e7485eb2/logo/icon.svg">
</a>
<div align="center">
<a href="https://evilmartians.com/?utm_source=postcss">
<img
src="https://evilmartians.com/badges/sponsored-by-evil-martians.svg"
alt="Sponsored by Evil Martians"
width="236"
height="54"
vspace="10">
</a>
</div>
</div>
[![npm][npm]][npm-url]
[![node][node]][node-url]
[![deps][deps]][deps-url]
[![tests][tests]][tests-url]
[![coverage][cover]][cover-url]
[![size][size]][size-url]
Webpack chat: [![chat][chat]][chat-url]
PostCSS chat: [![chat-postcss][chat-postcss]][chat-postcss-url]
# postcss-loader
Loader to process CSS with [`PostCSS`](https://github.com/postcss/postcss).
## Getting Started
You need webpack v5 to use the latest version. For Webpack v4, you have to install postcss-loader v4.
To begin, you'll need to install `postcss-loader` and `postcss`:
```console
npm install --save-dev postcss-loader postcss
```
Then add the plugin to your `webpack` config. For example:
> In the following configuration the plugin [`postcss-preset-env`](https://github.com/csstools/postcss-preset-env) is used, which is not installed by default.
**file.js**
```js
import css from "file.css";
```
**webpack.config.js**
```js
module.exports = {
module: {
rules: [
{
test: /\.css$/i,
use: [
"style-loader",
"css-loader",
{
loader: "postcss-loader",
options: {
postcssOptions: {
plugins: [
[
"postcss-preset-env",
{
// Options
},
],
],
},
},
},
],
},
],
},
};
```
Alternative use with [config files](#config):
**postcss.config.js**
```js
module.exports = {
plugins: [
[
"postcss-preset-env",
{
// Options
},
],
],
};
```
The loader **automatically** searches for configuration files.
**webpack.config.js**
```js
module.exports = {
module: {
rules: [
{
test: /\.css$/i,
use: ["style-loader", "css-loader", "postcss-loader"],
},
],
},
};
```
And run `webpack` via your preferred method.
## Options
| Name | Type | Default | Description |
| :---------------------------------: | :------------------: | :-----------------------------------: | :------------------------------------------- |
| [`execute`](#execute) | `{Boolean}` | `undefined` | Enable PostCSS Parser support in `CSS-in-JS` |
| [`postcssOptions`](#postcssOptions) | `{Object\|Function}` | `defaults values for Postcss.process` | Set `PostCSS` options and plugins |
| [`sourceMap`](#sourcemap) | `{Boolean}` | `compiler.devtool` | Enables/Disables generation of source maps |
| [`implementation`](#implementation) | `{Function\|String}` | `postcss` | Setup PostCSS implementation to use |
### `execute`
Type: `Boolean`
Default: `undefined`
If you use JS styles the [`postcss-js`](https://github.com/postcss/postcss-js) parser, add the `execute` option.
**webpack.config.js**
```js
module.exports = {
module: {
rules: [
{
test: /\.style.js$/,
use: [
"style-loader",
{
loader: "css-loader",
},
{
loader: "postcss-loader",
options: {
postcssOptions: {
parser: "postcss-js",
},
execute: true,
},
},
],
},
],
},
};
```
### `postcssOptions`
Type: `Object|Function`
Default: `undefined`
Allows to set [`PostCSS options`](https://postcss.org/api/#processoptions) and plugins.
All `PostCSS` options are supported.
There is the special `config` option for config files. How it works and how it can be configured is described below.
We recommend do not specify `from`, `to` and `map` options, because this can lead to wrong path in source maps.
If you need source maps please use the [`sourcemap`](#sourcemap) option.
#### `Object`
Setup `plugins`:
**webpack.config.js** (**recommended**)
```js
const myOtherPostcssPlugin = require("postcss-my-plugin");
module.exports = {
module: {
rules: [
{
test: /\.sss$/i,
loader: "postcss-loader",
options: {
postcssOptions: {
plugins: [
"postcss-import",
["postcss-short", { prefix: "x" }],
require.resolve("my-postcss-plugin"),
myOtherPostcssPlugin({ myOption: true }),
// Deprecated and will be removed in the next major release
{ "postcss-nested": { preserveEmpty: true } },
],
},
},
},
],
},
};
```
**webpack.config.js** (**deprecated**, will be removed in the next major release)
```js
module.exports = {
module: {
rules: [
{
test: /\.sss$/i,
loader: "postcss-loader",
options: {
postcssOptions: {
plugins: {
"postcss-import": {},
"postcss-short": { prefix: "x" },
},
},
},
},
],
},
};
```
Setup `syntax`:
**webpack.config.js**
```js
module.exports = {
module: {
rules: [
{
test: /\.sss$/i,
loader: "postcss-loader",
options: {
postcssOptions: {
// Can be `String`
syntax: "sugarss",
// Can be `Object`
syntax: require("sugarss"),
},
},
},
],
},
};
```
Setup `parser`:
**webpack.config.js**
```js
module.exports = {
module: {
rules: [
{
test: /\.sss$/i,
loader: "postcss-loader",
options: {
postcssOptions: {
// Can be `String`
parser: "sugarss",
// Can be `Object`
parser: require("sugarss"),
// Can be `Function`
parser: require("sugarss").parse,
},
},
},
],
},
};
```
Setup `stringifier`:
**webpack.config.js**
```js
const Midas = require("midas");
const midas = new Midas();
module.exports = {
module: {
rules: [
{
test: /\.sss$/i,
loader: "postcss-loader",
options: {
postcssOptions: {
// Can be `String`
stringifier: "sugarss",
// Can be `Object`
stringifier: require("sugarss"),
// Can be `Function`
stringifier: midas.stringifier,
},
},
},
],
},
};
```
#### `Function`
**webpack.config.js**
```js
module.exports = {
module: {
rules: [
{
test: /\.(css|sss)$/i,
loader: "postcss-loader",
options: {
postcssOptions: (loaderContext) => {
if (/\.sss$/.test(loaderContext.resourcePath)) {
return {
parser: "sugarss",
plugins: [
["postcss-short", { prefix: "x" }],
"postcss-preset-env",
],
};
}
return {
plugins: [
["postcss-short", { prefix: "x" }],
"postcss-preset-env",
],
};
},
},
},
],
},
};
```
#### `config`
Type: `Boolean|String`
Default: `undefined`
Allows to set options using config files.
Options specified in the config file are combined with options passed to the loader, the loader options overwrite options from config.
##### Config Files
The loader will search up the directory tree for configuration in the following places:
- a `postcss` property in `package.json`
- a `.postcssrc` file in JSON or YAML format
- a `.postcssrc.json`, `.postcssrc.yaml`, `.postcssrc.yml`, `.postcssrc.js`, or `.postcssrc.cjs` file
- a `postcss.config.js` or `postcss.config.cjs` CommonJS module exporting an object (**recommended**)
##### Examples of Config Files
Using `Object` notation:
**postcss.config.js** (**recommend**)
```js
module.exports = {
// You can specify any options from https://postcss.org/api/#processoptions here
// parser: 'sugarss',
plugins: [
// Plugins for PostCSS
["postcss-short", { prefix: "x" }],
"postcss-preset-env",
],
};
```
Using `Function` notation:
**postcss.config.js** (**recommend**)
```js
module.exports = (api) => {
// `api.file` - path to the file
// `api.mode` - `mode` value of webpack, please read https://webpack.js.org/configuration/mode/
// `api.webpackLoaderContext` - loader context for complex use cases
// `api.env` - alias `api.mode` for compatibility with `postcss-cli`
// `api.options` - the `postcssOptions` options
if (/\.sss$/.test(api.file)) {
return {
// You can specify any options from https://postcss.org/api/#processoptions here
parser: "sugarss",
plugins: [
// Plugins for PostCSS
["postcss-short", { prefix: "x" }],
"postcss-preset-env",
],
};
}
return {
// You can specify any options from https://postcss.org/api/#processoptions here
plugins: [
// Plugins for PostCSS
["postcss-short", { prefix: "x" }],
"postcss-preset-env",
],
};
};
```
**postcss.config.js** (**deprecated**, will be removed in the next major release)
```js
module.exports = {
// You can specify any options from https://postcss.org/api/#processoptions here
// parser: 'sugarss',
plugins: {
// Plugins for PostCSS
"postcss-short": { prefix: "x" },
"postcss-preset-env": {},
},
};
```
##### Config Cascade
You can use different `postcss.config.js` files in different directories.
Config lookup starts from `path.dirname(file)` and walks the file tree upwards until a config file is found.
```
| components
| | component
| | | index.js
| | | index.png
| | | style.css (1)
| | | postcss.config.js (1)
| | component
| | | index.js
| | | image.png
| | | style.css (2)
|
| postcss.config.js (1 && 2 (recommended))
| webpack.config.js
|
| package.json
```
After setting up your `postcss.config.js`, add `postcss-loader` to your `webpack.config.js`.
You can use it standalone or in conjunction with `css-loader` (recommended).
Use it **before** `css-loader` and `style-loader`, but **after** other preprocessor loaders like e.g `sass|less|stylus-loader`, if you use any (since [webpack loaders evaluate right to left/bottom to top](https://webpack.js.org/concepts/loaders/#configuration)).
**webpack.config.js** (**recommended**)
```js
module.exports = {
module: {
rules: [
{
test: /\.css$/,
use: [
"style-loader",
{
loader: "css-loader",
options: {
importLoaders: 1,
},
},
"postcss-loader",
],
},
],
},
};
```
#### Boolean
Enables/Disables autoloading config.
**webpack.config.js**
```js
module.exports = {
module: {
rules: [
{
test: /\.css$/i,
loader: "postcss-loader",
options: {
postcssOptions: {
config: false,
},
},
},
],
},
};
```
#### String
Allows to specify the path to the config file.
**webpack.config.js**
```js
const path = require("path");
module.exports = {
module: {
rules: [
{
test: /\.css$/i,
loader: "postcss-loader",
options: {
postcssOptions: {
config: path.resolve(__dirname, "custom.config.js"),
},
},
},
],
},
};
```
### `sourceMap`
Type: `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$/i,
use: [
{ loader: "style-loader" },
{ loader: "css-loader", options: { sourceMap: true } },
{ loader: "postcss-loader", options: { sourceMap: true } },
{ loader: "sass-loader", options: { sourceMap: true } },
],
},
],
},
};
```
Alternative setup:
**webpack.config.js**
```js
module.exports = {
devtool: "source-map",
module: {
rules: [
{
test: /\.css$/i,
use: [
{ loader: "style-loader" },
{ loader: "css-loader" },
{ loader: "postcss-loader" },
{ loader: "sass-loader" },
],
},
],
},
};
```
### `implementation`
Type: `Function | String`
Default: `postcss`
The special `implementation` option determines which implementation of PostCSS to use. Overrides the locally installed `peerDependency` version of `postcss`.
**This option is only really useful for downstream tooling authors to ease the PostCSS 7-to-8 transition.**
#### Function
**webpack.config.js**
```js
module.exports = {
module: {
rules: [
{
test: /\.css$/i,
use: [
{ loader: "style-loader" },
{ loader: "css-loader" },
{
loader: "postcss-loader",
options: { implementation: require("postcss") },
},
{ loader: "sass-loader" },
],
},
],
},
};
```
#### String
**webpack.config.js**
```js
module.exports = {
module: {
rules: [
{
test: /\.css$/i,
use: [
{ loader: "style-loader" },
{ loader: "css-loader" },
{
loader: "postcss-loader",
options: { implementation: require.resolve("postcss") },
},
{ loader: "sass-loader" },
],
},
],
},
};
```
## Examples
### SugarSS
You'll need to install `sugarss`:
```console
npm install --save-dev sugarss
```
Using [`SugarSS`](https://github.com/postcss/sugarss) syntax.
**webpack.config.js**
```js
module.exports = {
module: {
rules: [
{
test: /\.sss$/i,
use: [
"style-loader",
{
loader: "css-loader",
options: { importLoaders: 1 },
},
{
loader: "postcss-loader",
options: {
postcssOptions: {
parser: "sugarss",
},
},
},
],
},
],
},
};
```
### Autoprefixer
You'll need to install `autoprefixer`:
```console
npm install --save-dev autoprefixer
```
Add vendor prefixes to CSS rules using [`autoprefixer`](https://github.com/postcss/autoprefixer).
**webpack.config.js**
```js
module.exports = {
module: {
rules: [
{
test: /\.css$/i,
use: [
"style-loader",
{
loader: "css-loader",
options: { importLoaders: 1 },
},
{
loader: "postcss-loader",
options: {
postcssOptions: {
plugins: [
[
"autoprefixer",
{
// Options
},
],
],
},
},
},
],
},
],
},
};
```
> :warning: [`postcss-preset-env`](https://github.com/csstools/postcss-preset-env) includes [`autoprefixer`](https://github.com/postcss/autoprefixer), so adding it separately is not necessary if you already use the preset. More [information](https://github.com/csstools/postcss-preset-env#autoprefixer)
### PostCSS Preset Env
You'll need to install `postcss-preset-env`:
```console
npm install --save-dev postcss-preset-env
```
**webpack.config.js**
```js
module.exports = {
module: {
rules: [
{
test: /\.css$/i,
use: [
"style-loader",
{
loader: "css-loader",
options: { importLoaders: 1 },
},
{
loader: "postcss-loader",
options: {
postcssOptions: {
plugins: [
[
"postcss-preset-env",
{
// Options
},
],
],
},
},
},
],
},
],
},
};
```
### CSS Modules
What is `CSS Modules`? Please [read](https://github.com/webpack-contrib/css-loader#modules).
No additional options required on the `postcss-loader` side.
To make them work properly, either add the `css-loader`s `importLoaders` option.
**webpack.config.js**
```js
module.exports = {
module: {
rules: [
{
test: /\.css$/i,
use: [
"style-loader",
{
loader: "css-loader",
options: {
modules: true,
importLoaders: 1,
},
},
"postcss-loader",
],
},
],
},
};
```
### CSS-in-JS and [`postcss-js`](https://github.com/postcss/postcss-js)
You'll need to install `postcss-js`:
```console
npm install --save-dev postcss-js
```
If you want to process styles written in JavaScript, use the [`postcss-js`](https://github.com/postcss/postcss-js) parser.
**webpack.config.js**
```js
module.exports = {
module: {
rules: [
{
test: /\.style.js$/,
use: [
"style-loader",
{
loader: "css-loader",
options: {
importLoaders: 2,
},
},
{
loader: "postcss-loader",
options: {
postcssOptions: {
parser: "postcss-js",
},
execute: true,
},
},
"babel-loader",
],
},
],
},
};
```
As result you will be able to write styles in the following way
```js
import colors from "./styles/colors";
export default {
".menu": {
color: colors.main,
height: 25,
"&_link": {
color: "white",
},
},
};
```
> :warning: If you are using Babel you need to do the following in order for the setup to work
> 1. Add [`babel-plugin-add-module-exports`](https://github.com/59naga/babel-plugin-add-module-exports) to your configuration.
> 2. You need to have only one **default** export per style module.
### Extract CSS
Using [`mini-css-extract-plugin`](https://github.com/webpack-contrib/mini-css-extract-plugin).
**webpack.config.js**
```js
const isProductionMode = process.env.NODE_ENV === "production";
const MiniCssExtractPlugin = require("mini-css-extract-plugin");
module.exports = {
mode: isProductionMode ? "production" : "development",
module: {
rules: [
{
test: /\.css$/,
use: [
isProductionMode ? MiniCssExtractPlugin.loader : "style-loader",
"css-loader",
"postcss-loader",
],
},
],
},
plugins: [
new MiniCssExtractPlugin({
filename: isProductionMode ? "[name].[contenthash].css" : "[name].css",
}),
],
};
```
### Emit assets
To write a asset from PostCSS plugin to the webpack, need to add a message in `result.messages`.
The message should contain the following fields:
- `type` = `asset` - Message type (require, should be equal `asset`)
- `file` - file name (require)
- `content` - file content (require)
- `sourceMap` - sourceMap
- `info` - asset info
**webpack.config.js**
```js
const customPlugin = () => (css, result) => {
result.messages.push({
type: "asset",
file: "sprite.svg",
content: "<svg>...</svg>",
});
};
const postcssPlugin = postcss.plugin("postcss-assets", customPlugin);
module.exports = {
module: {
rules: [
{
test: /\.css$/i,
use: [
"style-loader",
"css-loader",
{
loader: "postcss-loader",
options: {
postcssOptions: {
plugins: [postcssPlugin()],
},
},
},
],
},
],
},
};
```
### Add dependencies, contextDependencies, buildDependencies, missingDependencies
The dependencies are necessary for webpack to understand when it needs to run recompilation on the changed files.
There are two way to add dependencies:
1. (Recommended). The plugin may emit messages in `result.messages`.
The message should contain the following fields:
- `type` = `dependency` - Message type (require, should be equal `dependency`, `context-dependency`, `build-dependency` or `missing-dependency`)
- `file` - absolute file path (require)
**webpack.config.js**
```js
const path = require("path");
const customPlugin = () => (css, result) => {
result.messages.push({
type: "dependency",
file: path.resolve(__dirname, "path", "to", "file"),
});
};
const postcssPlugin = postcss.plugin("postcss-assets", customPlugin);
module.exports = {
module: {
rules: [
{
test: /\.css$/i,
use: [
"style-loader",
"css-loader",
{
loader: "postcss-loader",
options: {
postcssOptions: {
plugins: [postcssPlugin()],
},
},
},
],
},
],
},
};
```
2. Pass `loaderContext` in plugin.
**webpack.config.js**
```js
const path = require("path");
module.exports = {
module: {
rules: [
{
test: /\.css$/i,
use: [
"style-loader",
"css-loader",
{
loader: "postcss-loader",
options: {
postcssOptions: {
config: path.resolve(__dirname, "path/to/postcss.config.js"),
},
},
},
],
},
],
},
};
```
**postcss.config.js**
```js
module.exports = (api) => ({
plugins: [
require("path/to/customPlugin")({
loaderContext: api.webpackLoaderContext,
}),
],
});
```
**customPlugin.js**
```js
const path = require("path");
const customPlugin = (loaderContext) => (css, result) => {
loaderContext.webpack.addDependency(
path.resolve(__dirname, "path", "to", "file")
);
};
module.exports = postcss.plugin("postcss-assets", customPlugin);
```
## 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/postcss-loader.svg
[npm-url]: https://npmjs.com/package/postcss-loader
[node]: https://img.shields.io/node/v/postcss-loader.svg
[node-url]: https://nodejs.org
[deps]: https://david-dm.org/webpack-contrib/postcss-loader.svg
[deps-url]: https://david-dm.org/webpack-contrib/postcss-loader
[tests]: https://github.com/webpack-contrib/postcss-loader/workflows/postcss-loader/badge.svg
[tests-url]: https://github.com/webpack-contrib/postcss-loader/actions
[cover]: https://codecov.io/gh/webpack-contrib/postcss-loader/branch/master/graph/badge.svg
[cover-url]: https://codecov.io/gh/webpack-contrib/postcss-loader
[chat]: https://badges.gitter.im/webpack/webpack.svg
[chat-url]: https://gitter.im/webpack/webpack
[chat-postcss]: https://badges.gitter.im/postcss/postcss.svg
[chat-postcss-url]: https://gitter.im/postcss/postcss
[size]: https://packagephobia.now.sh/badge?p=postcss-loader
[size-url]: https://packagephobia.now.sh/result?p=postcss-loader