code: function query (options$$1, next) {
  
      var urlParams = Object.keys(Url.options.params), query = {}, url = next(options$$1);
  
      each(options$$1.params, function (value, key) {
          if (urlParams.indexOf(key) === -1) {
              query[key] = value;
          }
      });
  
      query = Url.params(query);
  
      if (query) {
          url += (url.indexOf('?') == -1 ? '?' : '&') + query;
      }
  
      return url;
  }
docs: Query Parameter Transform.