singleWhereOrNull method

*<Null safety>*

T? singleWhereOrNull (bool test(T element))

Implementation

T? singleWhereOrNull(bool Function(T element) test) {
  T? result;
  var found = false;
  for (var element in this) {
    if (test(element)) {
      if (!found) {
        result = element;
        found = true;
      } else {
        return null;
      }
    }
  }
  return result;
}