retainWhere method

@override void retainWhere(bool test(T element))

Removes all objects from this list that fail to satisfy test.

An object o satisfies test if test(o) is true.

final numbers = <String>['one', 'two', 'three', 'four'];
numbers.retainWhere((item) => item.length == 3);
print(numbers); // [one, two]

The list must be growable.

Implementation

@override
void retainWhere(bool Function(T element) test) {
  if (lock) return _internal.retainWhere(test);
  final removed = <int, T>{};
  for (int index = 0; index < super.length; index++) {
    if (!test(super[index])) removed[index] = super[index];
  }
  if (removed.isNotEmpty) {
    lock = true;
    added = const {};
    this.removed = removed;
    changed = const {};
    _internal.retainWhere(test);
    notifyListeners();
  }
}