showdownjs/showdown

/**
 * Parse metadata at the top of the document
 */
showdown.subParser('makehtml.metadata', function (text, options, globals) {
  'use strict';

  if (!options.metadata) {
    return text;
  }

  text = globals.converter._dispatch('makehtml.metadata.before', text, options, globals).getText();

  function parseMetadataContents (content) {
    // raw is raw so it's not changed in any way
    globals.metadata.raw = content;

    // escape chars forbidden in html attributes
    // double quotes
    content = content
      // ampersand first
      .replace(/&/g, '&')
      // double quotes
      .replace(/"/g, '"');

    // Restore dollar signs and tremas
    content = content
      .replace(/¨D/g, '$$')
      .replace(/¨T/g, '¨');

    content = content.replace(/\n {4}/g, ' ');
    content.replace(/^([\S ]+): +([\s\S]+?)$/gm, function (wm, key, value) {
      globals.metadata.parsed[key] = value;
      return '';
    });
  }

  text = text.replace(/^\s*«««+\s*(\S*?)\n([\s\S]+?)\n»»»+\s*\n/, function (wholematch, format, content) {
    parseMetadataContents(content);
    return '¨M';
  });

  text = text.replace(/^\s*---+\s*(\S*?)\n([\s\S]+?)\n---+\s*\n/, function (wholematch, format, content) {
    if (format) {
      globals.metadata.format = format;
    }
    parseMetadataContents(content);
    return '¨M';
  });

  text = text.replace(/¨M/g, '');

  text = globals.converter._dispatch('makehtml.metadata.after', text, options, globals).getText();
  return text;
});