167 lines
4.5 KiB
Markdown
167 lines
4.5 KiB
Markdown
|
# PostCSS Custom Selectors [<img src="https://postcss.github.io/postcss/logo.svg" alt="PostCSS" width="90" height="90" align="right">][postcss]
|
||
|
|
||
|
[![NPM Version][npm-img]][npm-url]
|
||
|
[![CSS Standard Status][css-img]][css-url]
|
||
|
[![Build Status][cli-img]][cli-url]
|
||
|
[![Support Chat][git-img]][git-url]
|
||
|
|
||
|
[PostCSS Custom Selectors] lets you use Custom Selectors in CSS, following the
|
||
|
[CSS Extensions] specification.
|
||
|
|
||
|
```pcss
|
||
|
@custom-selector :--heading h1, h2, h3;
|
||
|
|
||
|
article :--heading + p {
|
||
|
margin-top: 0;
|
||
|
}
|
||
|
|
||
|
/* becomes */
|
||
|
|
||
|
article h1 + p, article h2 + p, article h3 + p {}
|
||
|
```
|
||
|
|
||
|
## Usage
|
||
|
|
||
|
Add [PostCSS Custom Selectors] to your project:
|
||
|
|
||
|
```bash
|
||
|
npm install postcss-custom-selectors --save-dev
|
||
|
```
|
||
|
|
||
|
Use [PostCSS Custom Selectors] to process your CSS:
|
||
|
|
||
|
```js
|
||
|
const postcssCustomSelectors = require('postcss-custom-selectors');
|
||
|
|
||
|
postcssCustomSelectors.process(YOUR_CSS /*, processOptions, pluginOptions */);
|
||
|
```
|
||
|
|
||
|
Or use it as a [PostCSS] plugin:
|
||
|
|
||
|
```js
|
||
|
const postcss = require('postcss');
|
||
|
const postcssCustomSelectors = require('postcss-custom-selectors');
|
||
|
|
||
|
postcss([
|
||
|
postcssCustomSelectors(/* pluginOptions */)
|
||
|
]).process(YOUR_CSS /*, processOptions */);
|
||
|
```
|
||
|
|
||
|
[PostCSS Custom Selectors] 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
|
||
|
|
||
|
### preserve
|
||
|
|
||
|
The `preserve` option determines whether custom selectors and rules using
|
||
|
custom selectors should be preserved in their original form.
|
||
|
|
||
|
```pcss
|
||
|
@custom-selector :--heading h1, h2, h3;
|
||
|
|
||
|
article :--heading + p {
|
||
|
margin-top: 0;
|
||
|
}
|
||
|
|
||
|
/* becomes */
|
||
|
|
||
|
article h1 + p, article h2 + p, article h3 + p {}
|
||
|
|
||
|
article :--heading + p {}
|
||
|
```
|
||
|
|
||
|
### importFrom
|
||
|
|
||
|
The `importFrom` option specifies sources where custom selectors can be
|
||
|
imported from, which might be CSS, JS, and JSON files, functions, and directly
|
||
|
passed objects.
|
||
|
|
||
|
```js
|
||
|
postcssCustomSelectors({
|
||
|
importFrom: 'path/to/file.css' // => @custom-selector :--heading h1, h2, h3;
|
||
|
});
|
||
|
```
|
||
|
|
||
|
```pcss
|
||
|
article :--heading + p {
|
||
|
margin-top: 0;
|
||
|
}
|
||
|
|
||
|
/* becomes */
|
||
|
|
||
|
article h1 + p, article h2 + p, article h3 + p {}
|
||
|
```
|
||
|
|
||
|
Multiple sources can be passed into this option, and they will be parsed in the
|
||
|
order they are received. JavaScript files, JSON files, functions, and objects
|
||
|
will need to namespace custom selectors using the `customProperties` or
|
||
|
`custom-properties` key.
|
||
|
|
||
|
```js
|
||
|
postcssCustomSelectors({
|
||
|
importFrom: [
|
||
|
'path/to/file.css',
|
||
|
'and/then/this.js',
|
||
|
'and/then/that.json',
|
||
|
{
|
||
|
customSelectors: { ':--heading': 'h1, h2, h3' }
|
||
|
},
|
||
|
() => {
|
||
|
const customProperties = { ':--heading': 'h1, h2, h3' };
|
||
|
|
||
|
return { customProperties };
|
||
|
}
|
||
|
]
|
||
|
});
|
||
|
```
|
||
|
|
||
|
### exportTo
|
||
|
|
||
|
The `exportTo` option specifies destinations where custom selectors can be
|
||
|
exported to, which might be CSS, JS, and JSON files, functions, and directly
|
||
|
passed objects.
|
||
|
|
||
|
```js
|
||
|
postcssCustomSelectors({
|
||
|
exportTo: 'path/to/file.css' // @custom-selector :--heading h1, h2, h3;
|
||
|
});
|
||
|
```
|
||
|
|
||
|
Multiple destinations can be passed into this option, and they will be parsed
|
||
|
in the order they are received. JavaScript files, JSON files, and objects will
|
||
|
need to namespace custom selectors using the `customProperties` or
|
||
|
`custom-properties` key.
|
||
|
|
||
|
```js
|
||
|
const cachedObject = { customSelectors: {} };
|
||
|
|
||
|
postcssCustomSelectors({
|
||
|
exportTo: [
|
||
|
'path/to/file.css', // @custom-selector :--heading h1, h2, h3;
|
||
|
'and/then/this.js', // module.exports = { customSelectors: { ':--heading': 'h1, h2, h3' } }
|
||
|
'and/then/this.mjs', // export const customSelectors = { ':--heading': 'h1, h2, h3' } }
|
||
|
'and/then/that.json', // { "custom-selectors": { ":--heading": "h1, h2, h3" } }
|
||
|
cachedObject,
|
||
|
customProperties => {
|
||
|
customProperties // { ':--heading': 'h1, h2, h3' }
|
||
|
}
|
||
|
]
|
||
|
});
|
||
|
```
|
||
|
|
||
|
[cli-img]: https://img.shields.io/travis/postcss/postcss-custom-selectors.svg
|
||
|
[cli-url]: https://travis-ci.org/postcss/postcss-custom-selectors
|
||
|
[css-img]: https://cssdb.org/badge/custom-selectors.svg
|
||
|
[css-url]: https://cssdb.org/#custom-selectors
|
||
|
[git-img]: https://img.shields.io/badge/support-chat-blue.svg
|
||
|
[git-url]: https://gitter.im/postcss/postcss
|
||
|
[npm-img]: https://img.shields.io/npm/v/postcss-custom-selectors.svg
|
||
|
[npm-url]: https://www.npmjs.com/package/postcss-custom-selectors
|
||
|
|
||
|
[CSS Extensions]: https://drafts.csswg.org/css-extensions/#custom-selectors
|
||
|
[PostCSS]: https://github.com/postcss/postcss
|
||
|
[PostCSS Custom Selectors]: https://github.com/postcss/postcss-custom-selectors
|