https://github.com/csstools/postcss-extend-rule
Use the extend at-rule and functional selectors in CSS
https://github.com/csstools/postcss-extend-rule
Last synced: 10 months ago
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Use the extend at-rule and functional selectors in CSS
- Host: GitHub
- URL: https://github.com/csstools/postcss-extend-rule
- Owner: csstools
- License: cc0-1.0
- Created: 2017-09-16T23:38:32.000Z (over 8 years ago)
- Default Branch: main
- Last Pushed: 2024-12-27T18:32:29.000Z (about 1 year ago)
- Last Synced: 2025-05-02T08:39:05.134Z (11 months ago)
- Language: JavaScript
- Homepage: https://jonathantneal.github.io/postcss-extend-rule/
- Size: 284 KB
- Stars: 51
- Watchers: 4
- Forks: 7
- Open Issues: 5
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- Contributing: CONTRIBUTING.md
- License: LICENSE.md
- Code of conduct: CODE_OF_CONDUCT.md
Awesome Lists containing this project
README
# PostCSS Extend Rule [
][postcss]
[![NPM Version][npm-img]][npm-url]
[](https://github.com/csstools/postcss-extend-rule/actions/workflows/test.yml)
[
][discord]
[PostCSS Extend Rule] lets you use the `@extend` at-rule and
[Functional Selectors] in CSS, following the speculative
[CSS Extend Rules Specification].
```pcss
%thick-border {
border: thick dotted red;
}
.serious-modal {
font-style: normal;
font-weight: bold;
@media (max-width: 240px) {
@extend .modal:hover;
}
}
.modal {
@extend %thick-border;
color: red;
}
.modal:hover:not(:focus) {
outline: none;
}
/* becomes */
.serious-modal {
font-style: normal;
font-weight: bold;
}
@media (max-width: 240px) {
.serious-modal:not(:focus) {
outline: none;
}
}
.modal {
border: thick dotted red;
color: red;
}
.modal:hover:not(:focus) {
outline: none;
}
```
## Usage
Add [PostCSS Extend Rule] to your project:
```bash
npm install postcss postcss-extend-rule --save-dev
```
Use **PostCSS Extend Rule** to process your CSS:
```js
const postcssExtendRule = require('postcss-extend-rule');
postcssExtendRule.process(YOUR_CSS /*, processOptions, pluginOptions */);
```
Or use it as a [PostCSS] plugin:
```js
const postcss = require('postcss');
const postcssExtendRule = require('postcss-extend-rule');
postcss([
postcssExtendRule(/* pluginOptions */)
]).process(YOUR_CSS /*, processOptions */);
```
**PostCSS Extend Rule** runs in all Node environments, with special instructions for:
| [Node](INSTALL.md#node) | [PostCSS CLI](INSTALL.md#postcss-cli) | [Webpack](INSTALL.md#webpack) | [Create React App](INSTALL.md#create-react-app) | [Gulp](INSTALL.md#gulp) | [Grunt](INSTALL.md#grunt) |
| --- | --- | --- | --- | --- | --- |
## Options
### name
The `name` option determines the at-rule name being used to extend selectors.
By default, this name is `extend`, meaning `@extend` rules are parsed.
```js
postcssExtend({ name: 'postcss-extend' })
```
If the `name` option were changed to, say, `postcss-extend`, then only
`@postcss-extend` at-rules would be parsed.
```pcss
main {
@postcss-extend .some-rule;
}
```
### onFunctionalSelector
The `onFunctionalSelector` option determines how functional selectors should be
handled. Its options are:
- `remove` (default) removes any functional selector
- `ignore` ignores any functional selector and moves on
- `warn` warns the user whenever it encounters a functional selector
- `throw` throws an error if ever it encounters a functional selector
```js
postcssExtend({ onFunctionalSelector: 'remove' /* default */ })
```
```pcss
%this-will-be-removed {}
```
### onRecursiveExtend
The `onRecursiveExtend` option determines how recursive extend at-rules should
be handled. Its options are:
- `remove` (default) removes any recursive extend at-rules
- `ignore` ignores any recursive extend at-rules and moves on
- `warn` warns the user whenever it encounters a recursive extend at-rules
- `throw` throws an error if ever it encounters a recursive extend at-rules
```js
postcssExtend({ onRecursiveExtend: 'remove' /* default */ })
```
```pcss
.this-will-not-extend-itself {
@extend .this-will-not-extend-itself;
}
```
### onUnusedExtend
The `onUnusedExtend` option determines how an unused extend at-rule should be
handled. Its options are:
- `remove` (default) removes any unused extend at-rule
- `ignore` ignores any unused extend at-rule and moves on
- `warn` warns the user whenever it encounters an unused extend at-rule
- `throw` throws an error if ever it encounters an unused extend at-rule
```js
postcssExtend({ onUnusedExtend: 'remove' /* default */ })
```
```pcss
main {
@extend .this-selector-does-not-exist-and-will-be-removed;
}
```
[git-img]: https://img.shields.io/badge/support-chat-blue.svg
[discord]: https://discord.gg/bUadyRwkJS
[npm-img]: https://img.shields.io/npm/v/postcss-extend-rule.svg
[npm-url]: https://www.npmjs.com/package/postcss-extend-rule
[CSS Extend Rules Specification]: https://jonathantneal.github.io/specs/css-extend-rule/
[Functional Selectors]: https://jonathantneal.github.io/specs/css-extend-rule/#functional-selector
[PostCSS]: https://github.com/postcss/postcss
[PostCSS Extend Rule]: https://github.com/csstools/postcss-extend-rule