postcss-syntax

What is postcss-syntax?

The postcss-syntax npm package is a syntax parser for PostCSS that allows you to parse and stringify CSS, LESS, SCSS, and other syntaxes in a unified way. It enables PostCSS to understand these various syntaxes, which can be useful for tasks such as linting, minification, and applying other PostCSS plugins to non-standard CSS files.

What are postcss-syntax's main functionalities?

Parsing CSS-like syntaxes

This feature allows you to use PostCSS to parse different CSS-like syntaxes such as SCSS or LESS. The code sample demonstrates how to process a source string with PostCSS using the postcss-syntax package to handle different syntaxes.

const postcss = require('postcss');
const syntax = require('postcss-syntax');

postcss(plugins).process(source, { syntax: syntax }).then(result => {
  console.log(result.content);
});

Stringifying parsed syntaxes

After parsing CSS-like syntaxes, postcss-syntax can also be used to stringify the parsed abstract syntax tree (AST) back into a CSS string. This is useful for transforming code and then outputting the result.

const postcss = require('postcss');
const syntax = require('postcss-syntax');

const root = postcss.parse(source, { syntax: syntax });
const css = root.toString(syntax);

Other packages similar to postcss-syntax

postcss-scss

This package is a SCSS parser for PostCSS. It allows you to work with SCSS syntax specifically, whereas postcss-syntax is more general and can handle multiple syntaxes.

postcss-less

Similar to postcss-scss, postcss-less is a parser that allows PostCSS to understand LESS syntax. It is specifically tailored for LESS, unlike postcss-syntax which is more versatile.

sugarss

SugarSS is an indented syntax parser for PostCSS. It is a more specialized tool compared to postcss-syntax, focusing on a syntax that is similar to Sass or Stylus but with a different set of features.

README

PostCSS Syntax

postcss-syntax can automatically switch the required PostCSS syntax by file extension/source

Getting Started

First thing's first, install the module:

npm install postcss-syntax --save-dev

If you want support SCSS/SASS/LESS/SugarSS syntax, you need to install these module:

• SCSS: postcss-scss
• SASS: postcss-sass
• LESS: postcss-less
• SugarSS: sugarss

If you want support HTML (and HTML-like)/Markdown/CSS-in-JS file format, you need to install these module:

• CSS-in-JS: postcss-jsx
• HTML (and HTML-like): postcss-html
• Markdown: postcss-markdown

Use Cases

const postcss = require('postcss');
const syntax = require('postcss-syntax')({
	rules: [
		{
			test: /\.(?:[sx]?html?|[sx]ht|vue|ux|php)$/i,
			extract: 'html',
		},
		{
			test: /\.(?:markdown|md)$/i,
			extract: 'markdown',
		},
		{
			test: /\.(?:m?[jt]sx?|es\d*|pac)$/i,
			extract: 'jsx',
		},
		{
			// custom language for file extension
			test: /\.postcss$/i,
			lang: 'scss'
		},
		{
			// custom language for file extension
			test: /\.customcss$/i,
			lang: 'custom'
		},
	],

	// custom parser for CSS (using `postcss-safe-parser`)
	css: 'postcss-safe-parser',
	// custom parser for SASS (PostCSS-compatible syntax.)
	sass: require('postcss-sass'),
	// custom parser for SCSS (by module name)
	scss: 'postcss-scss',
	// custom parser for LESS (by module path)
	less: './node_modules/postcss-less',
	// custom parser for SugarSS
	sugarss: require('sugarss'),
	// custom parser for custom language
	custom: require('postcss-custom-syntax'),

});
postcss(plugins).process(source, { syntax: syntax }).then(function (result) {
	// An alias for the result.css property. Use it with syntaxes that generate non-CSS output.
	result.content
});