useTimeoutFn function

TimeoutState useTimeoutFn(VoidCallback fn, Duration delay)

Calls given function after specified duration. Provides handles to cancel and/or reset the timeout.

Implementation

TimeoutState useTimeoutFn(VoidCallback fn, Duration delay) {
  final isReady = useRef<bool?>(null);
  final timeout = useRef<Timer?>(null);
  final callback = useRef(fn);

  // update ref when function changes
  // ignore: body_might_complete_normally_nullable
  useEffect(() {
    callback.value = fn;
  }, [fn]);

  final getIsReady = useCallback<bool? Function()>(() {
    return isReady.value;
  }, const []);

  final reset = useCallback(() {
    isReady.value = false;
    timeout.value?.cancel();
    timeout.value = Timer(delay, () {
      isReady.value = true;
      callback.value();
    });
  }, const []);

  final cancel = useCallback(() {
    isReady.value = null;
    timeout.value?.cancel();
  }, const []);

  final state = useRef(TimeoutState(getIsReady, cancel, reset));

  // set on mount, clear on unmount
  useEffect(() {
    reset();

    return cancel;
  }, [delay]);

  return state.value;
}