retainAll method

@override void retainAll(Iterable<Object?> elements)

Removes all elements of this set that are not elements in elements. Listeners are notified after all values have been removed.

Checks for each element of elements whether there is an element in this set that is equal to it (according to this.contains), and if so, the equal element in this set is retained, and elements that are not equal to any elements in elements are removed.

Implementation

@override
void retainAll(Iterable<Object?> elements) {
  assert(_debugAssertNotDisposed());
  _set!.retainAll(elements);
  notifyListeners();
}