containsKey method Null safety

  1. @override
bool containsKey(
  1. Object? key
)
override

Whether this map contains the given key.

Returns true if any of the keys in the map are equal to key according to the equality used by the map.

final moonCount = <String, int>{'Mercury': 0, 'Venus': 0, 'Earth': 1,
  'Mars': 2, 'Jupiter': 79, 'Saturn': 82, 'Uranus': 27, 'Neptune': 14 };
final containsUranus = moonCount.containsKey('Uranus'); // true
final containsPluto = moonCount.containsKey('Pluto'); // false

Implementation

@override
bool containsKey(Object? key) {
  if (!_isValidKey(key)) return false;
  return _base.containsKey(_canonicalize(key as K));
}