javascript.js

/*
Language: JavaScript
Description: JavaScript (JS) is a lightweight, interpreted, or just-in-time compiled programming language with first-class functions.
Category: common, scripting
Website: https://developer.mozilla.org/en-US/docs/Web/JavaScript
*/

import * as ECMAScript from "./lib/ecmascript";
import * as regex from "../lib/regex";

export default function(hljs) {
  var IDENT_RE = ECMAScript.IDENT_RE;
  var FRAGMENT = {
    begin: '<>',
    end: '</>'
  };
  var XML_TAG = {
    begin: /<[A-Za-z0-9\\._:-]+/,
    end: /\/[A-Za-z0-9\\._:-]+>|\/>/
  };
  var KEYWORDS = {
    $pattern: ECMAScript.IDENT_RE,
    keyword: ECMAScript.KEYWORDS.join(" "),
    literal: ECMAScript.LITERALS.join(" "),
    built_in: ECMAScript.BUILT_INS.join(" ")
  };
  var NUMBER = {
    className: 'number',
    variants: [
      { begin: '\\b(0[bB][01]+)n?' },
      { begin: '\\b(0[oO][0-7]+)n?' },
      { begin: hljs.C_NUMBER_RE + 'n?' }
    ],
    relevance: 0
  };
  var SUBST = {
    className: 'subst',
    begin: '\\$\\{', end: '\\}',
    keywords: KEYWORDS,
    contains: []  // defined later
  };
  var HTML_TEMPLATE = {
    begin: 'html`', end: '',
    starts: {
      end: '`', returnEnd: false,
      contains: [
        hljs.BACKSLASH_ESCAPE,
        SUBST
      ],
      subLanguage: 'xml',
    }
  };
  var CSS_TEMPLATE = {
    begin: 'css`', end: '',
    starts: {
      end: '`', returnEnd: false,
      contains: [
        hljs.BACKSLASH_ESCAPE,
        SUBST
      ],
      subLanguage: 'css',
    }
  };
  var TEMPLATE_STRING = {
    className: 'string',
    begin: '`', end: '`',
    contains: [
      hljs.BACKSLASH_ESCAPE,
      SUBST
    ]
  };
  SUBST.contains = [
    hljs.APOS_STRING_MODE,
    hljs.QUOTE_STRING_MODE,
    HTML_TEMPLATE,
    CSS_TEMPLATE,
    TEMPLATE_STRING,
    NUMBER,
    hljs.REGEXP_MODE
  ];
  var PARAMS_CONTAINS = SUBST.contains.concat([
    // eat recursive parens in sub expressions
    { begin: /\(/, end: /\)/,
      contains: ["self"].concat(SUBST.contains, [hljs.C_BLOCK_COMMENT_MODE, hljs.C_LINE_COMMENT_MODE])
    },
    hljs.C_BLOCK_COMMENT_MODE,
    hljs.C_LINE_COMMENT_MODE
  ]);
  var PARAMS = {
    className: 'params',
    begin: /\(/, end: /\)/,
    excludeBegin: true,
    excludeEnd: true,
    contains: PARAMS_CONTAINS
  };

  return {
    name: 'JavaScript',
    aliases: ['js', 'jsx', 'mjs', 'cjs'],
    keywords: KEYWORDS,
    contains: [
      hljs.SHEBANG({
        binary: "node",
        relevance: 5
      }),
      {
        className: 'meta',
        relevance: 10,
        begin: /^\s*['"]use (strict|asm)['"]/
      },
      hljs.APOS_STRING_MODE,
      hljs.QUOTE_STRING_MODE,
      HTML_TEMPLATE,
      CSS_TEMPLATE,
      TEMPLATE_STRING,
      hljs.C_LINE_COMMENT_MODE,
      hljs.COMMENT(
        '/\\*\\*',
        '\\*/',
        {
          relevance : 0,
          contains : [
            {
              className : 'doctag',
              begin : '@[A-Za-z]+',
              contains : [
                {
                  className: 'type',
                  begin: '\\{',
                  end: '\\}',
                  relevance: 0
                },
                {
                  className: 'variable',
                  begin: IDENT_RE + '(?=\\s*(-)|$)',
                  endsParent: true,
                  relevance: 0
                },
                // eat spaces (not newlines) so we can find
                // types or variables
                {
                  begin: /(?=[^\n])\s/,
                  relevance: 0
                },
              ]
            }
          ]
        }
      ),
      hljs.C_BLOCK_COMMENT_MODE,
      NUMBER,
      { // object attr container
        begin: regex.concat(/[{,\n]\s*/,
          // we need to look ahead to make sure that we actually have an
          // attribute coming up so we don't steal a comma from a potential
          // "value" container
          //
          // NOTE: this might not work how you think.  We don't actually always
          // enter this mode and stay.  Instead it might merely match `,
          // <comments up next>` and then immediately end after the , because it
          // fails to find any actual attrs. But this still does the job because
          // it prevents the value contain rule from grabbing this instead and
          // prevening this rule from firing when we actually DO have keys.
          regex.lookahead(regex.concat(
            // we also need to allow for multiple possible comments inbetween
            // the first key:value pairing
            /(((\/\/.*)|(\/\*(.|\n)*\*\/))\s*)*/,
            IDENT_RE + '\\s*:'))),
        relevance: 0,
        contains: [
          {
            className: 'attr',
            begin: IDENT_RE + regex.lookahead('\\s*:'),
            relevance: 0,
          },
        ]
      },
      { // "value" container
        begin: '(' + hljs.RE_STARTERS_RE + '|\\b(case|return|throw)\\b)\\s*',
        keywords: 'return throw case',
        contains: [
          hljs.C_LINE_COMMENT_MODE,
          hljs.C_BLOCK_COMMENT_MODE,
          hljs.REGEXP_MODE,
          {
            className: 'function',
            // we have to count the parens to make sure we actually have the
            // correct bounding ( ) before the =>.  There could be any number of
            // sub-expressions inside also surrounded by parens.
            begin: '(\\([^(]*' +
              '(\\([^(]*' +
                '(\\([^(]*' +
                '\\))?' +
              '\\))?' +
            '\\)|' + hljs.UNDERSCORE_IDENT_RE + ')\\s*=>', returnBegin: true,
            end: '\\s*=>',
            contains: [
              {
                className: 'params',
                variants: [
                  {
                    begin: hljs.UNDERSCORE_IDENT_RE
                  },
                  {
                    className: null,
                    begin: /\(\s*\)/,
                    skip: true
                  },
                  {
                    begin: /\(/, end: /\)/,
                    excludeBegin: true, excludeEnd: true,
                    keywords: KEYWORDS,
                    contains: PARAMS_CONTAINS
                  }
                ]
              }
            ]
          },
          { // could be a comma delimited list of params to a function call
            begin: /,/, relevance: 0,
          },
          {
            className: '',
            begin: /\s/,
            end: /\s*/,
            skip: true,
          },
          { // JSX
            variants: [
              { begin: FRAGMENT.begin, end: FRAGMENT.end },
              { begin: XML_TAG.begin, end: XML_TAG.end }
            ],
            subLanguage: 'xml',
            contains: [
              {
                begin: XML_TAG.begin, end: XML_TAG.end, skip: true,
                contains: ['self']
              }
            ]
          },
        ],
        relevance: 0
      },
      {
        className: 'function',
        beginKeywords: 'function', end: /\{/, excludeEnd: true,
        contains: [
          hljs.inherit(hljs.TITLE_MODE, {begin: IDENT_RE}),
          PARAMS
        ],
        illegal: /\[|%/
      },
      {
        begin: /\$[(.]/ // relevance booster for a pattern common to JS libs: `$(something)` and `$.something`
      },

      hljs.METHOD_GUARD,
      { // ES6 class
        className: 'class',
        beginKeywords: 'class', end: /[{;=]/, excludeEnd: true,
        illegal: /[:"\[\]]/,
        contains: [
          {beginKeywords: 'extends'},
          hljs.UNDERSCORE_TITLE_MODE
        ]
      },
      {
        beginKeywords: 'constructor', end: /\{/, excludeEnd: true
      },
      {
        begin: '(get|set)\\s+(?=' + IDENT_RE + '\\()',
        end: /{/,
        keywords: "get set",
        contains: [
          hljs.inherit(hljs.TITLE_MODE, {begin: IDENT_RE}),
          { begin: /\(\)/ }, // eat to avoid empty params
          PARAMS
        ]

      }
    ],
    illegal: /#(?!!)/
  };
}