int last

Source 

int get last {
  if (string.length == 0) {
    throw new StateError('No elements.');
  }
  int length = string.length;
  int code = string.codeUnitAt(length - 1);
  if (_isTrailSurrogate(code) && string.length > 1) {
    int previousCode = string.codeUnitAt(length - 2);
    if (_isLeadSurrogate(previousCode)) {
      return _combineSurrogatePair(previousCode, code);
    }
  }
  return code;
}