Map after an operation has been applied to each key and
value in the current
public function mapWithKey<Tu>(
): Map<Tk, Tu>;
Every key and value in the current
Map is affected by a call to
filterWithKey() where only values that meet a
certain criteria are affected.
The keys will remain unchanged from the current
Map to the returned
Map. The keys are only used to help in the mapping operation.
(function(Tk,Tv):Tu) $callback - The callback containing the operation to apply to the
Map keys and values.
Map<Tk, Tu> - a
Map containing the values after a user-specified operation
on the current
Map's keys and values is applied.