Function getsert

getsert<K, V>(map, key, valueGenerator): V
Get, or insert then get, a value from the map.
Type Parameters
- K
- V
Parameters
- map: Map<K, V>
  Map to get the value from.
- key: K
  Key of the value to retrieve
- valueGenerator: (() => V)
  Method used to generate a value for the key if it is not currently in the map.
  - - (): V
    - Returns V
Returns V