Socket
Socket
Sign inDemoInstall

postcss-custom-properties

Package Overview
Dependencies
9
Maintainers
5
Versions
82
Alerts
File Explorer

Advanced tools

Install Socket

Detect and block malicious and high-risk dependencies

Install

postcss-custom-properties

Use Custom Properties Queries in CSS


Version published
Maintainers
5
Weekly downloads
6,393,184
increased by2.59%
Bundle size
13.2 kB
Minified + gzipped

Weekly downloads

Readme

Source

PostCSS Custom Properties PostCSS Logo

npm version Build Status Discord

Baseline Status CSS Standard Status

npm install postcss-custom-properties --save-dev

PostCSS Custom Properties lets you use Custom Properties in CSS, following the CSS Custom Properties specification.

'Can I use' table

:root {
	--color-blue-dark: rgb(0, 61, 184);
	--color-blue-light: rgb(0, 217, 255);
	--color-pink: rgb(255, 192, 211);
	--text-color: var(--color-pink);
}

.element {
	/* custom props */
	--border-color: var(--color-blue-light);

	/* props */
	border: 1px solid var(--border-color);
	color: var(--text-color);
}

.element--dark {
	--border-color: var(--color-blue-dark);
}

/* becomes */

:root {
	--color-blue-dark: rgb(0, 61, 184);
	--color-blue-light: rgb(0, 217, 255);
	--color-pink: rgb(255, 192, 211);
	--text-color: var(--color-pink);
}

.element {
	/* custom props */
	--border-color: var(--color-blue-light);

	/* props */
	border: 1px solid rgb(0, 217, 255);
	border: 1px solid var(--border-color);
	color: rgb(255, 192, 211);
	color: var(--text-color);
}

.element--dark {
	--border-color: var(--color-blue-dark);
}

Note:

  • Only processes variables that were defined in the :root or html selector.
  • Locally defined variables will be used as fallbacks only within the same rule, but not elsewhere.
  • Fallback values in var() will be used if the variable was not defined in the :root or html selector.

Usage

Add PostCSS Custom Properties to your project:

npm install postcss postcss-custom-properties --save-dev

Use it as a PostCSS plugin:

const postcss = require('postcss');
const postcssCustomProperties = require('postcss-custom-properties');

postcss([
	postcssCustomProperties(/* pluginOptions */)
]).process(YOUR_CSS /*, processOptions */);

PostCSS Custom Properties runs in all Node environments, with special instructions for:

Options

preserve

The preserve option determines whether properties using custom properties should be preserved in their original form. By default these are preserved.

Custom property declarations are always preserved only var() functions can be omitted.

postcssCustomProperties({ preserve: false })
:root {
	--color-blue-dark: rgb(0, 61, 184);
	--color-blue-light: rgb(0, 217, 255);
	--color-pink: rgb(255, 192, 211);
	--text-color: var(--color-pink);
}

.element {
	/* custom props */
	--border-color: var(--color-blue-light);

	/* props */
	border: 1px solid var(--border-color);
	color: var(--text-color);
}

.element--dark {
	--border-color: var(--color-blue-dark);
}

/* becomes */

:root {
	--color-blue-dark: rgb(0, 61, 184);
	--color-blue-light: rgb(0, 217, 255);
	--color-pink: rgb(255, 192, 211);
	--text-color: var(--color-pink);
}

.element {
	/* custom props */
	--border-color: var(--color-blue-light);

	/* props */
	border: 1px solid var(--border-color);
	color: rgb(255, 192, 211);
}

.element--dark {
	--border-color: var(--color-blue-dark);
}

Modular CSS Processing

If you're using Modular CSS such as, CSS Modules, postcss-loader or vanilla-extract to name a few, you'll probably notice that custom properties are not being resolved. This happens because each file is processed separately so unless you import the custom properties definitions in each file, they won't be resolved.

To overcome this, we recommend using the PostCSS Global Data plugin which allows you to pass a list of files that will be globally available. The plugin won't inject any extra code in the output but will provide the context needed to resolve custom properties.

For it to run it needs to be placed before the PostCSS Custom Properties plugin.

const postcss = require('postcss');
const postcssCustomProperties = require('postcss-custom-properties');
const postcssGlobalData = require('@csstools/postcss-global-data');

postcss([
	postcssGlobalData({
		files: [
			'path/to/your/custom-selectors.css'
		]
	}),
	postcssCustomProperties(/* pluginOptions */)
]).process(YOUR_CSS /*, processOptions */);

Keywords

FAQs

Last updated on 11 Apr 2024

Did you know?

Socket for GitHub automatically highlights issues in each pull request and monitors the health of all your open source dependencies. Discover the contents of your packages and block harmful activity before you install or update your dependencies.

Install

Related posts

SocketSocket SOC 2 Logo

Product

  • Package Alerts
  • Integrations
  • Docs
  • Pricing
  • FAQ
  • Roadmap

Stay in touch

Get open source security insights delivered straight into your inbox.


  • Terms
  • Privacy
  • Security

Made with ⚡️ by Socket Inc