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


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

That is, takes the continuous prefix of values in the current ImmVector for which the specified callback returns true.

The returned ImmVector will always be a subset (but not necessarily a proper subset) of the current ImmVector.


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

Return Values


See Vector::takeWhile for usage examples.