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