index.js

var patternRegex = /(((?:\{|\｛)[^\}\｝]+(?:\}|\｝)(?:\（|\()[^\}\｝]+(?:\）|\)))+)/g;
var kanjiRegex = /(?:\{|\｛)([^\}\｝]+)(?:\}|\｝)(?:\（|\()([^\}\｝]+)(?:\）|\))/g;

var KanjiExtension = function(converter) {
  return [
    {
      type: 'lang',
      filter: function(text) {
        var match;

        while (match = patternRegex.exec(text)) {
          var html = ["<ruby>"];
          var phrase = match[0];

          while (secondMatch = kanjiRegex.exec(phrase)) {
            var kanji = secondMatch[1];
            var reading = secondMatch[2];

            html.push(kanji);
            html.push("<rt>");
            html.push(reading);
            html.push("</rt>");
          }

          html.push("</ruby>");

          text = match.input.replace(phrase, html.join(""));
        }

        return text;
      }
    }
  ];
}

module.exports = KanjiExtension;