debounce method Null safety

ValueListenable<T> debounce(
  1. Duration timeOut
)

If you get too much value changes during a short time period and you don't want or can handle them all debounce can help you. If you add a debounce to your listenable processing pipeline the returned ValueListenable will not emit an updated value before at least timpeout time has passed since the last value change. All value changes before will be discarded.

ATTENTION: If you use debounce inside the Widget tree in combination with setState it can happen that debounce doesn't have any effect. Better to use it inside your model objects

example:

final listenable = ValueNotifier<int>(0);

listenable
    .debounce(const Duration(milliseconds: 500))
    .listen((x, _) => print(x));

listenable.value = 42;
await Future.delayed(const Duration(milliseconds: 100));
listenable.value = 43;
await Future.delayed(const Duration(milliseconds: 100));
listenable.value = 44;
await Future.delayed(const Duration(milliseconds: 350));
listenable.value = 45;
await Future.delayed(const Duration(milliseconds: 550));
listenable.value = 46;

will print out 45

Implementation

ValueListenable<T> debounce(Duration timeOut) {
  return DebouncedValueNotifier(this.value, this, timeOut);
}