contains method Null safety

  1. @override
bool contains(
  1. Object? E
)

Whether the collection contains an element equal to element.

This operation will check each element in order for being equal to element, unless it has a more efficient way to find an element equal to element.

The equality used to determine whether element is equal to an element of the iterable defaults to the Object.== of the element.

Some types of iterable may have a different equality used for its elements. For example, a Set may have a custom equality (see Set.identity) that its contains uses. Likewise the Iterable returned by a Map.keys call should use the same equality that the Map uses for keys.

Implementation

@override
bool contains(Object? E) => _values.contains(E);