code: function(str) {
    // Replace repeat characters.
    str = str
      .replace(/(..)々々/g, '$1$1')
      .replace(/(.)々/g, '$1$1');
  
    str = converters.normalize(str);
    str = converters.fixFullwidthKana(str);
  
    // Replace composite symbols.
    str = fixCompositeSymbols(str);
  
    return str;
  }
docs: Fix kana and apply the following processes;
  * Replace repeat characters
  * Alphabet to halfwidth
  * Numbers to halfwidth
  * Punctuation to fullwidth
  * Katakana to fullwidth
  * Fix fullwidth kana
  * Replace composite symbols
  
  @param {string} str
  @return {string}