update method Null safety

E update(
  1. int index,
  2. E newValue
)

Set the element at index to newValue.

The old value at index is returned. The listeners will be notified.

Implementation

E update(int index, E newValue) {
  E oldValue = elementAt(index);
  replace(elementAt(index), newValue);
  notifyListeners();
  return oldValue;
}