Returns an ImmMap containing the values of the current ImmMap that meet a supplied condition

public function filter(
  (function(Tv):bool) $callback,
): ImmMap<Tk, Tv>;

Only values that meet a certain criteria are affected by a call to filter(), while all values are affected by a call to map().

The keys associated with the current ImmMap remain unchanged in the returned Map.


  • (function(Tv):bool) $callback - The callback containing the condition to apply to the current ImmMap values.

Return Values