code: function(data) {
              var paramArray = [],
                  key, value;
              for (key in data) {
                  value = data[key];
                  key = ENCODE_URI_COMPONENT(key);
                  paramArray.push((value === null) ? key : (key + "=" + ENCODE_URI_COMPONENT(value)));
              }
              return paramArray.join("&");
          }
docs: Stringifies an object into one string with every pair separated by `&`
  
  @method _toQueryString
  @param data {Object} containing key-value pairs
  @return {String} stringified presentation of the object, with every pair separated by `&`
  @private