HH\KeyedIterable::firstKey
Returns the first key in the current KeyedIterable
public function firstKey(): ?Tk;
Returns
?Tk- The first key in the currentKeyedIterable, ornullif the currentKeyedIterableis empty.
Returns the first key in the current KeyedIterable
public function firstKey(): ?Tk;
?Tk - The first key in the current KeyedIterable, or null if the
current KeyedIterable is empty.