code: function (data) {
              // Convert string to WordArray, else assume WordArray already
              if (typeof data == 'string') {
                  data = Utf8.parse(data);
              }
  
              // Append
              this._data.concat(data);
              this._nDataBytes += data.sigBytes;
          }
docs: Adds new data to this block algorithm's buffer.
  
  @param {WordArray|string} data The data to append. Strings are converted to a WordArray using UTF-8.
  
  @example
  
  bufferedBlockAlgorithm._append('data');
  bufferedBlockAlgorithm._append(wordArray);