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CSSTree

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CSSTree is a tool set for CSS: fast detailed parser (CSS → AST), walker (AST traversal), generator (AST → CSS) and lexer (validation and matching) based on specs and browser implementations. The main goal is to be efficient and W3C spec compliant, with focus on CSS analyzing and source-to-source transforming tasks.

Features

Projects using CSSTree

Documentation

Tools

Related projects

Usage

Install with npm:

npm install css-tree

Basic usage:

import * as csstree from 'css-tree';

// parse CSS to AST
const ast = csstree.parse('.example { world: "!" }');

// traverse AST and modify it
csstree.walk(ast, (node) => {
    if (node.type === 'ClassSelector' && node.name === 'example') {
        node.name = 'hello';
    }
});

// generate CSS from AST
console.log(csstree.generate(ast));
// .hello{world:"!"}

Syntax matching:

// parse CSS to AST as a declaration value
const ast = csstree.parse('red 1px solid', { context: 'value' });

// match to syntax of `border` property
const matchResult = csstree.lexer.matchProperty('border', ast);

// check first value node is a <color>
console.log(matchResult.isType(ast.children.first, 'color'));
// true

// get a type list matched to a node
console.log(matchResult.getTrace(ast.children.first));
// [ { type: 'Property', name: 'border' },
//   { type: 'Type', name: 'color' },
//   { type: 'Type', name: 'named-color' },
//   { type: 'Keyword', name: 'red' } ]

Exports

Is it possible to import just a needed part of library like a parser or a walker. That's might useful for loading time or bundle size optimisations.

import * as tokenizer from 'css-tree/tokenizer';
import * as parser from 'css-tree/parser';
import * as walker from 'css-tree/walker';
import * as lexer from 'css-tree/lexer';
import * as definitionSyntax from 'css-tree/definition-syntax';
import * as data from 'css-tree/definition-syntax-data';
import * as dataPatch from 'css-tree/definition-syntax-data-patch';
import * as utils from 'css-tree/utils';

Using in a browser

Bundles are available for use in a browser:

<script src="node_modules/css-tree/dist/csstree.js"></script>
<script>
  csstree.parse('.example { color: green }');
</script>
<script type="module">
  import { parse } from 'node_modules/css-tree/dist/csstree.esm.js'
  parse('.example { color: green }');
</script>

One of CDN services like unpkg or jsDelivr can be used. By default (for short path) a ESM version is exposing. For IIFE version a full path to a bundle should be specified:

<!-- ESM -->
<script type="module">
  import * as csstree from 'https://cdn.jsdelivr.net/npm/css-tree';
  import * as csstree from 'https://unpkg.com/css-tree';
</script>

<!-- IIFE with an export to global -->
<script src="https://cdn.jsdelivr.net/npm/css-tree/dist/csstree.js"></script>
<script src="https://unpkg.com/css-tree/dist/csstree.js"></script>

Top level API

API map

License

MIT