Returns an ImmMap containing the keys and values of the current ImmMap up to but not including the first value that produces false when passed to the specified callback

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

The returned ImmMap will always be a proper subset of the current ImmMap.


  • (function(Tv):bool) $callback

Return Values