css.js

/*
Language: CSS
Category: common, css, web
Website: https://developer.mozilla.org/en-US/docs/Web/CSS
*/

// @ts-ignore
import * as css from "./lib/css-shared.js";

/** @type LanguageFn */
export default function(hljs) {
  const regex = hljs.regex;
  const modes = css.MODES(hljs);
  const VENDOR_PREFIX = { begin: /-(webkit|moz|ms|o)-(?=[a-z])/ };
  const AT_MODIFIERS = "and or not only";
  const AT_PROPERTY_RE = /@-?\w[\w]*(-\w+)*/; // @-webkit-keyframes
  const IDENT_RE = '[a-zA-Z-][a-zA-Z0-9_-]*';
  const STRINGS = [
    hljs.APOS_STRING_MODE,
    hljs.QUOTE_STRING_MODE
  ];

  return {
    name: 'CSS',
    case_insensitive: true,
    illegal: /[=|'\$]/,
    keywords: { keyframePosition: "from to" },
    classNameAliases: {
      // for visual continuity with `tag {}` and because we
      // don't have a great class for this?
      keyframePosition: "selector-tag" },
    contains: [
      modes.BLOCK_COMMENT,
      VENDOR_PREFIX,
      // to recognize keyframe 40% etc which are outside the scope of our
      // attribute value mode
      modes.CSS_NUMBER_MODE,
      {
        className: 'selector-id',
        begin: /#[A-Za-z0-9_-]+/,
        relevance: 0
      },
      {
        className: 'selector-class',
        begin: '\\.' + IDENT_RE,
        relevance: 0
      },
      modes.ATTRIBUTE_SELECTOR_MODE,
      {
        className: 'selector-pseudo',
        variants: [
          { begin: ':(' + css.PSEUDO_CLASSES.join('|') + ')' },
          { begin: ':(:)?(' + css.PSEUDO_ELEMENTS.join('|') + ')' }
        ]
      },
      // we may actually need this (12/2020)
      // { // pseudo-selector params
      //   begin: /\(/,
      //   end: /\)/,
      //   contains: [ hljs.CSS_NUMBER_MODE ]
      // },
      modes.CSS_VARIABLE,
      {
        className: 'attribute',
        begin: '\\b(' + css.ATTRIBUTES.join('|') + ')\\b'
      },
      // attribute values
      {
        begin: /:/,
        end: /[;}{]/,
        contains: [
          modes.BLOCK_COMMENT,
          modes.HEXCOLOR,
          modes.IMPORTANT,
          modes.CSS_NUMBER_MODE,
          ...STRINGS,
          // needed to highlight these as strings and to avoid issues with
          // illegal characters that might be inside urls that would tigger the
          // languages illegal stack
          {
            begin: /(url|data-uri)\(/,
            end: /\)/,
            relevance: 0, // from keywords
            keywords: { built_in: "url data-uri" },
            contains: [
              ...STRINGS,
              {
                className: "string",
                // any character other than `)` as in `url()` will be the start
                // of a string, which ends with `)` (from the parent mode)
                begin: /[^)]/,
                endsWithParent: true,
                excludeEnd: true
              }
            ]
          },
          modes.FUNCTION_DISPATCH
        ]
      },
      {
        begin: regex.lookahead(/@/),
        end: '[{;]',
        relevance: 0,
        illegal: /:/, // break on Less variables @var: ...
        contains: [
          {
            className: 'keyword',
            begin: AT_PROPERTY_RE
          },
          {
            begin: /\s/,
            endsWithParent: true,
            excludeEnd: true,
            relevance: 0,
            keywords: {
              $pattern: /[a-z-]+/,
              keyword: AT_MODIFIERS,
              attribute: css.MEDIA_FEATURES.join(" ")
            },
            contains: [
              {
                begin: /[a-z-]+(?=:)/,
                className: "attribute"
              },
              ...STRINGS,
              modes.CSS_NUMBER_MODE
            ]
          }
        ]
      },
      {
        className: 'selector-tag',
        begin: '\\b(' + css.TAGS.join('|') + ')\\b'
      }
    ]
  };
}