Once-only onEnd

onEnd fires once per generation. restart() creates a new generation and allows it to fire again.

Once-only onEndLive

Once-only callback

00:05

idle

1. waiting for first end event

useTimer({
  autoStart: true,
  endWhen: snapshot => snapshot.elapsedMilliseconds >= 5000,
  onEnd: () => api.markDone(),
});