code: function toQueryString(o, fn) {
      if (!isPlainObject(o))
        throw Error('artoo.writers.queryString: wrong arguments.');
  
      var s = '',
          k;
  
      for (k in o) {
        s +=
          (s ? '&' : '') +
          k + '=' +
          encodeURIComponent(typeof fn === 'function' ? fn(o[k]) : o[k]);
      }
  
      return s;
    }
docs: Web Formats
  ------------
  
  Converts JavaScript data into standard web formats such as querystrings.