docs: function(data) {
              var paramArray = [],
                  key, value;
          // TODO: use `object` module
              for (key in data) {
                  value = data[key];
                  key = ENCODE_URI_COMPONENT(key);
                  paramArray.push((value === null) ? key : (key + '=' + ENCODE_URI_COMPONENT(value)));
              }
              console.log(NAME, '_toQueryString --> '+paramArray.join('&'));
              return paramArray.join('&');
          }