useState<T> function

({void Function() dispose, T Function() get, Observable<T> o, FutureOr<void> Function(FutureOr<T>) set, FutureOr<void> Function(FutureOr<T> (T prev)) update}) useState<T>(T initialValue)

Record to expose Observable and T Function() and FutureOr<void> Function(T) and FutureOr<void> Function(T Function(T)) and void Function() to create state with provided initialValue.

final count = useState(50);
count.setCount(5); // [ASYNC SUPPORTED]

Update Value

count.update((prev) => prev + 10); // [ASYNC SUPPORTED]

Read Value

final updated = count.get();

Records :

• Observable | o
• T Function() | get();
• void Function(T) | set(T);
• void Function(T Function(T) | update(T Function(T))
• void Function() | dispose();

Args

• T initialValue

Implementation

({
  Observable<T> o,
  T Function() get,
  FutureOr<void> Function(FutureOr<T>) set,
  FutureOr<void> Function(FutureOr<T> Function(T prev)) update,
  void Function() dispose
}) useState<T>(T initialValue) {
  final controller = StreamController<T>.broadcast();
  void dispose() => controller.close();

  final o = Observable<T>(initialValue, controller);

  T get() => o.value;

  return (
    o: o,
    get: get,

    /// Direct setter
    set: (modifier) async => o._notify(await modifier),

    /// Update with prev value
    update: (modifier) async => o._notify(await modifier(o.value)),

    /// Controller disposer
    dispose: dispose
  );
}