toggle method

Observer<List<E>> toggle(
  1. E element, [
  2. bool? alreadyInserted
])

Implementation

Observer<List<E>> toggle(E element, [bool? alreadyInserted]) {
  bool isInserted = alreadyInserted ?? value.contains(element);
  if (isInserted) {
    value = value..remove(element);
  } else {
    value = value..add(element);
  }
  return this;
}