postcss-nesting

What is postcss-nesting?

The postcss-nesting package is a PostCSS plugin that allows you to use nesting syntax in CSS, similar to what is offered by preprocessors like Sass and Less. It helps to write more readable and maintainable CSS by allowing styles to be nested within one another.

What are postcss-nesting's main functionalities?

Nesting Rules

Allows nesting of selectors within a parent selector, which will be expanded to the equivalent of 'a b { color: black; }'.

a {
  & b { color: black; }
}

Nesting Properties

Enables nesting of properties, which is useful for grouping font properties or other related properties together.

a {
  font: {
    weight: bold;
    size: 1em;
    family: serif;
  }
}

Nesting At-Rules

Supports nesting of at-rules like @media within a selector, which will be processed into the correct CSS syntax.

a {
  @media (min-width: 500px) {
    color: black;
  }
}

Other packages similar to postcss-nesting

postcss-nested

Similar to postcss-nesting, postcss-nested allows for nesting of selectors within CSS. It follows the nesting rules of preprocessors like Sass rather than the CSS Nesting Module.

postcss-preset-env

This package includes postcss-nesting as one of its features, among other future CSS features, and allows you to use them in current browsers.

postcss-scss

This is a syntax plugin for PostCSS that allows you to work with SCSS syntax, including nesting, but it does not compile SCSS. It's useful for linting SCSS with stylelint and PostCSS.

README

CSS Nesting

CSS Nesting allows you to nest one style rule inside another, following the CSS Nesting Module Level 3 specification.

/* at rule nesting */

a, b {
	color: red;

	@nest & c, & d {
		color: white;
	}

	@nest & & {
		color: blue;
	}

	@nest &:hover {
		color: black;
	}

	@media (min-width: 30em) {
		color: yellow;
	}
}

/* direct nesting */

a, b {
	color: red;

	& c, & d {
		color: white;
	}

	& & {
		color: blue;
	}

	&:hover {
		color: black;
	}

	@media (min-width: 30em) {
		color: yellow;
	}
}

/* after */

a, b {
    color: red;
}

a c, a d, b c, b d {
    color: white;
}

a a, b b {
    color: blue;
}

a:hover, b:hover {
    color: black;
}

@media (min-width: 30em) {
    a, b {
        color: yellow;
    }
}

Usage

Add CSS Nesting to your build tool:

npm install postcss-nesting --save-dev

Node

require('postcss-nesting').process(YOUR_CSS, { /* options */ });

PostCSS

Add PostCSS to your build tool:

npm install postcss --save-dev

Load CSS Nesting as a PostCSS plugin:

postcss([
	require('postcss-nesting')({ /* options */ })
]).process(YOUR_CSS, /* options */);

Gulp

Add Gulp PostCSS to your build tool:

npm install gulp-postcss --save-dev

Enable CSS Nesting within your Gulpfile:

var postcss = require('gulp-postcss');

gulp.task('css', function () {
	return gulp.src('./src/*.css').pipe(
		postcss([
			require('postcss-nesting')({ /* options */ })
		])
	).pipe(
		gulp.dest('.')
	);
});

Grunt

Add Grunt PostCSS to your build tool:

npm install grunt-postcss --save-dev

Enable CSS Nesting within your Gruntfile:

grunt.loadNpmTasks('grunt-postcss');

grunt.initConfig({
	postcss: {
		options: {
			use: [
				require('postcss-nesting')({ /* options */ })
			]
		},
		dist: {
			src: '*.css'
		}
	}
});

Options

bubble

Type: Array
Default: ['document', 'media', 'supports']

Specifies additional at-rules whose contents should be transpiled so that the at-rule comes first. By default, @media, @supports and @document will do this.

prefix

Type: String
Default: null

Specifies a prefix to be surrounded by dashes before the @nest at-rule (e.g. @-x-nest).