description

# containsKey abstract method

bool containsKey(

1. Object? key

)

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

    bool containsKey(Object? key);