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A modern CSS parser and stringifier with TypeScript support

Parse CSS into an Abstract Syntax Tree (AST) and convert it back to CSS with configurable formatting. Built with TypeScript for type safety and modern JavaScript features.

npm install @adobe/css-tools

import{parse,stringify}from'@adobe/css-tools'// Parse CSS to ASTconstast=parse('body { font-size: 12px; }')// Stringify AST back to CSSconstcss=stringify(ast)// => "body { font-size: 12px; }"// Pretty print with custom indentationconstformatted=stringify(ast,{indent:'  '})// => "body {\n  font-size: 12px;\n}"// Minify outputconstminified=stringify(ast,{compress:true})// => "body{font-size:12px}"

Parses CSS code and returns an Abstract Syntax Tree (AST).

Parameters:

• code (string) - The CSS code to parse
• options (object, optional) - Parsing options
  • silent (boolean) - Silently fail on parse errors instead of throwing
  • source (string) - File path for better error reporting

Returns:CssStylesheetAST - The parsed CSS as an AST

Converts a CSS AST back to CSS string with configurable formatting.

Parameters:

• ast (CssStylesheetAST) - The CSS AST to stringify
• options (object, optional) - Stringification options
  • indent (string) - Indentation string (default:' ')
  • compress (boolean) - Whether to compress/minify the output (default:false)

Returns:string - The formatted CSS string

• Complete CSS Support: All standard CSS features including selectors, properties, values, at-rules, and comments
• TypeScript Support: Full type definitions for all AST nodes and functions
• Error Handling: Configurable error handling with detailed position information
• Formatting Options: Pretty print, minify, or custom formatting
• Performance Optimized: Efficient parsing and stringification for large CSS files
• Source Maps: Track original source positions for debugging and tooling

• Selectors: Element, class, ID, attribute, pseudo-class, pseudo-element selectors
• Properties: All standard CSS properties and custom properties
• Values: Colors, lengths, percentages, functions, calc(), etc.
• At-rules: @media, @keyframes, @import, @charset, @namespace, @font-face, @page, @document, @supports, @container, @layer, @starting-style, @host, @custom-media
• Comments: Both /* */ and // comments
• Whitespace: Preserves formatting information
• Vendor prefixes: Supports vendor-prefixed at-rules and properties
• Nested rules: Media queries, supports, containers, etc.
• Complex selectors: Combinators, pseudo-selectors, attribute selectors

import{parse}from'@adobe/css-tools'constmalformedCss=`  body { color: red; }  { color: blue; } /* Missing selector */  .valid { background: green; }`// Parse with silent error handlingconstresult=parse(malformedCss,{silent:true})// Check for parsing errorsif(result.stylesheet.parsingErrors){console.log('Parsing errors:',result.stylesheet.parsingErrors.length)result.stylesheet.parsingErrors.forEach(error=>{console.log(`Error at line${error.line}:${error.message}`)})}// Valid rules are still parsedconsole.log('Valid rules:',result.stylesheet.rules.length)

import{parse}from'@adobe/css-tools'constcss='body { color: red; }'constast=parse(css,{source:'styles.css'})// Position information is availableconstrule=ast.stylesheet.rules[0]console.log(rule.position?.source)// "styles.css"console.log(rule.position?.start)// { line: 1, column: 1 }console.log(rule.position?.end)// { line: 1, column: 20 }

For more examples, see theExamples documentation.

The library is optimized for performance and can handle large CSS files efficiently. For benchmarking information, see thebenchmark/ directory in the source code.

• API Reference - Complete API documentation
• AST Structure - Detailed AST node types and structure
• Examples - Comprehensive usage examples
• Changelog - Version history and changes

This is a fork of the npmcss package, maintained by Adobe with modern improvements including TypeScript support, enhanced performance, and security updates. It provides a robust foundation for CSS tooling, preprocessing, and analysis.

MIT