refractor/lang/handlebars.js

Lightweight, robust, elegant virtual syntax highlighting using Prism

'use strict';

module.exports = handlebars;
handlebars.displayName = 'handlebars';
handlebars.aliases = [];
function handlebars(Prism) {
  (function(Prism) {
    var handlebars_pattern = /\{\{\{[\s\S]+?\}\}\}|\{\{[\s\S]+?\}\}/;
    Prism.languages.handlebars = Prism.languages.extend('markup', {
      handlebars: {
        pattern: handlebars_pattern,
        inside: {
          delimiter: {
            pattern: /^\{\{\{?|\}\}\}?$/i,
            alias: 'punctuation'
          },
          string: /(["'])(?:\\.|(?!\1)[^\\\r\n])*\1/,
          number: /\b-?(?:0x[\dA-Fa-f]+|\d*\.?\d+(?:[Ee][+-]?\d+)?)\b/,
          boolean: /\b(?:true|false)\b/,
          block: {
            pattern: /^(\s*~?\s*)[#\/]\S+?(?=\s*~?\s*$|\s)/i,
            lookbehind: true,
            alias: 'keyword'
          },
          brackets: {
            pattern: /\[[^\]]+\]/,
            inside: {
              punctuation: /\[|\]/,
              variable: /[\s\S]+/
            }
          },
          punctuation: /[!"#%&'()*+,.\/;<=>@\[\\\]^`{|}~]/,
          variable: /[^!"#%&'()*+,.\/;<=>@\[\\\]^`{|}~\s]+/
        }
      }
    });
    // Comments are inserted at top so that they can
    // surround markup
    Prism.languages.insertBefore('handlebars', 'tag', {
      'handlebars-comment': {
        pattern: /\{\{![\s\S]*?\}\}/,
        alias: ['handlebars', 'comment']
      }
    });
    // Tokenize all inline Handlebars expressions that are wrapped in {{ }} or {{{ }}}
    // This allows for easy Handlebars + markup highlighting
    Prism.hooks.add('before-highlight', function(env) {
      if (env.language !== 'handlebars') {
        return;
      }
      env.tokenStack = [];
      env.backupCode = env.code;
      env.code = env.code.replace(handlebars_pattern, function(match) {
        var i = env.tokenStack.length;
        // Check for existing strings
        while (env.backupCode.indexOf('___HANDLEBARS' + i + '___') !== -1) ++i;
        // Create a sparse array
        env.tokenStack[i] = match;
        return '___HANDLEBARS' + i + '___';
      });
    });
    // Restore env.code for other plugins (e.g. line-numbers)
    Prism.hooks.add('before-insert', function(env) {
      if (env.language === 'handlebars') {
        env.code = env.backupCode;
        delete env.backupCode;
      }
    });
    // Re-insert the tokens after highlighting
    // and highlight them with defined grammar
    Prism.hooks.add('after-highlight', function(env) {
      if (env.language !== 'handlebars') {
        return;
      }
      for (
        var i = 0, keys = Object.keys(env.tokenStack);
        i < keys.length;
        ++i
      ) {
        var k = keys[i];
        var t = env.tokenStack[k];
        // The replace prevents $$, $&, $`, $', $n, $nn from being interpreted as special patterns
        env.highlightedCode = env.highlightedCode.replace(
          '___HANDLEBARS' + k + '___',
          Prism.highlight(t, env.grammar, 'handlebars').replace(/\$/g, '$$$$')
        );
      }
      env.element.innerHTML = env.highlightedCode;
    });
  })(Prism);
}