docs: function validateQueryParams() {
          var queryString;
          if (config.queryParams) {
              if (typeof config.queryParams === 'string') {
                  // strip '?' if it's there, because we add it below
                  queryString = config.queryParams.replace(/^\?/, '');
              } else {
                  queryString = util.param(config.queryParams);
              }
          }
          config.queryString = queryString ? '?' + queryString : '';
      }