cssprima - The most standards compliant CSS parser, written in JavaScript.

This project is intended to be a reference implementation to the latest Editor's Draft of the CSS Syntax Level 3 specification. As this edition of the specification evolves, so will the implementation.

The code attempts to follow the specification verbatim, with the least amount of code additions possible.

Usage

npm i cssprima

Examples

Tokenize a selector.

> cssprima.tokenize('#headlines:nth-child(2n)');
[ { type: 'Hash',
    typeFlag: 'id',
    value: 'headlines' },
  { type: 'Colon', value: ':' },
  { type: 'Function', value: 'nth-child' },
  { type: 'Dimension',
    repr: '2',
    value: 2,
    typeFlag: 'integer',
    unit: 'n' },
  { type: 'RightParen', value: ')' } ]

Parse a rule.

> var rule = '.clearfix { clear: both; }';
undefined
> cssprima.parseRule(rule);
{ type: 'QualifiedRule',
  prelude:
   [ { type: 'Delim', value: '.' },
     { type: 'Identifier', value: 'clearfix' },
     { type: 'Whitespace', value: ' ' } ],
  value: null,
  block:
   { type: 'SimpleBlock',
     associatedToken: { type: 'LeftBrace' },
     value:
      [ { type: 'Whitespace', value: ' ' },
        { type: 'Identifier', value: 'clear' },
        { type: 'Colon', value: ':' },
        { type: 'Whitespace', value: ' ' },
        { type: 'Identifier', value: 'both' },
        { type: 'Semicolon', value: ';' },
        { type: 'Whitespace', value: ' ' } ] } }

Possible object types:

> cssprima.Types
{ IDENT: 'Identifier',
  FUNCTION: 'Function',
  AT_KEYWORD: 'AtKeyword',
  HASH: 'Hash',
  STRING: 'String',
  BAD_STRING: 'BadString',
  URL: 'URL',
  BAD_URL: 'BadURL',
  DELIM: 'Delim',
  NUMBER: 'Number',
  PERCENTAGE: 'Percentage',
  DIMENSION: 'Dimension',
  UNICODE_RANGE: 'UnicodeRange',
  INCLUDE_MATCH: 'IncludeMatch',
  ... }

Other API methods:

• parseStylesheet
• parseRules
• parseDeclaration
• parseDeclarations
• parseComponentValue
• parseComponentValues
• parseCommaSeparatedComponentValues

Testing

This project passes css-parsing-tests, written by the specification's co-author Simon Sapin.

$ npm test

> [email protected] test c:\Users\ezequiel\Desktop\cssprima
> tap test/tap/*.js

ok test/tap/parsing.js .............................. 136/136
total ............................................... 136/136

ok

Notes

• Not entirely ready for use, but is for the most part.
• There's still a lot more to do (documentation, examples, code cleansing. ...).