# keys property

Iterable<K> keys

The keys of this.

The returned iterable has efficient `length` and `contains` operations, based on length and containsKey of the map.

The order of iteration is defined by the individual `Map` implementation, but must be consistent between changes to the map.

Modifying the map while iterating the keys may break the iteration.

## Implementation

    Iterable<K> get keys;