Package Exports
- postcss-custom-selectors
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Readme
PostCSS Custom Selectors
PostCSS plugin to transform W3C CSS Extensions(Custom Selectors) to more compatible CSS.
Installation
$ npm install postcss-custom-selectors
Quick Start
// dependencies
var fs = require('fs')
var postcss = require('postcss')
var selector = require('postcss-custom-selectors')
// css to be processed
var css = fs.readFileSync('input.css', 'utf8')
// process css using postcss-custom-selectors
var output = postcss()
.use(selector())
.process(css)
.css
console.log('\n====>Output CSS:\n', output)
Or just:
var output = postcss(selector())
.process(css)
.css
input:
@custom-selector :--heading h1, h2, h3, h4, h5, h6;
article :--heading + p {
margin-top: 0;
}
You will get:
article h1 + p,
article h2 + p,
article h3 + p,
article h4 + p,
article h5 + p,
article h6 + p {
margin-top: 0;
}
CSS syntax
@custom-selector = @custom-selector :<extension-name> <selector>;
How to use
The custom selector is a pseudo-class, so you must use :--
to define it.
For example to simulate :any-link selector:
@custom-selector :--any-link :link, :visited;
a:--any-link {
color: blue;
}
output:
a:link,
a:visited {
color: blue;
}
You can even make some smart use like this:
@custom-selector :--button button, .button;
@custom-selector :--enter :hover, :focus;
:--button:--enter {
}
output
button:hover,
.button:hover,
button:focus,
.button:focus {
}
Options
lineBreak
(default: true
)
Set whether multiple selector wrap.The default is turning on to be a newline.
Close the line breaks.
var options = {
lineBreak: false
}
var output = postcss(selector(options))
.process(css)
.css
With the first example, the output will be:
article h1 + p, article h2 + p, article h3 + p, article h4 + p, article h5 + p, article h6 + p {
margin-top: 0;
}
extensions
(default: {}
)
This option allows you to customize an object to set the <extension-name>
(selector alias) and <selector>
, these definitions will cover the same alias of @custom-selector
in CSS.
var options = {
extensions: {
':--any' : 'section, article, aside, nav'
}
}
var output = postcss(selector(options))
.process(css)
.css;
input.css
@custom-selector :--any .foo, .bar; /* No effect */
:--any h1 {
margin-top: 16px;
}
output:
/* No effect */
section h1,
article h1,
aside h1,
nav h1 {
margin-top: 16px;
}
transformMatches
(default: true
)
Allows you to limit transformation to :matches()
usage
If set to false:
input
@custom-selector :--foo .bar, .baz;
.foo:--foo {
margin-top: 16px;
}
output
.foo:matches(.bar, .baz) {
margin-top: 16px;
}
Usage
Node Watch
Dependence chokidar module.
var fs = require('fs')
var chokidar = require('chokidar')
var postcss = require('postcss')
var selector = require('postcss-custom-selectors')
var src = 'input.css'
console.info('Watching…\nModify the input.css and save.')
chokidar.watch(src, {
ignored: /[\/\\]\./,
persistent: true
}).on('all',
function(event, path, stats) {
var css = fs.readFileSync(src, 'utf8')
var output = postcss(selector())
.process(css)
.css
fs.writeFileSync('output.css', output)
})
Grunt
module.exports = function(grunt) {
grunt.initConfig({
pkg: grunt.file.readJSON('package.json'),
postcss: {
options: {
processors: [
require('autoprefixer-core')({ browsers: ['> 0%'] }).postcss, //Other plugin
require('postcss-custom-selectors')(),
]
},
dist: {
src: ['src/*.css'],
dest: 'build/grunt.css'
}
}
});
grunt.loadNpmTasks('grunt-contrib-uglify');
grunt.loadNpmTasks('grunt-postcss');
grunt.registerTask('default', ['postcss']);
}
Gulp
var gulp = require('gulp');
var rename = require('gulp-rename');
var postcss = require('gulp-postcss');
var selector = require('postcss-custom-selectors')
var autoprefixer = require('autoprefixer-core')
gulp.task('default', function () {
var processors = [
autoprefixer({ browsers: ['> 0%'] }), //Other plugin
selector()
];
gulp.src('src/*.css')
.pipe(postcss(processors))
.pipe(rename('gulp.css'))
.pipe(gulp.dest('build'))
});
gulp.watch('src/*.css', ['default']);
Contributing
- Install the relevant dependent module.
- Respect coding style(Install EditorConfig).
- Add test cases in the test directory.
- Run test.
$ git clone https://github.com/postcss/postcss-custom-selectors.git
$ git checkout -b patch
$ npm install
$ npm test