All the keys of the map.
The size of the map.
Associate the given key with the given value in the map.
Key to set in the map.
Value to be associated with the key.
Associate the given key with the given value in the map only if the key has not been set in the map.
Key to set in the map.
Value to be associated with the key.
Optional
errorMessage: stringMessage to log if the key already has a value.
true
if the operation is successful, false
if it is not.
A map of string keys to some ValueType.