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

public function takeWhile(
  (function(Tv):bool) $fn,
): ConstMap<Tk, Tv>;

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


  • (function(Tv):bool) $fn - The callback that is used to determine the stopping condition.

Return Values