Manage Lifecycle topic

Manage Lifecycle

A screen often starts several pieces of reactive work together: remote search, analytics, subscriptions, maybe a watcher for transitions.

When they share one lifecycle, put them in an EffectScope:

final EffectScope _scope = EffectScope();

void dispose() {
  _scope.dispose();
}

Create related reactions inside run():

_scope.run(() {
  Effect(() {
    final text = session.query.value.trim();
    if (text.isEmpty) return;

    final timer = Timer(const Duration(milliseconds: 300), () {
      unawaited(remoteSearch(text));
    });

    onEffectCleanup(timer.cancel);
  });
});

The scope disposes the effect created inside run(). It also runs cleanup registered by that effect, such as the debounce timer cancellation.

A watcher can join the same scope:

_scope.run(() {
  Watcher<int>(
    () => session.results.value.length,
    (next, previous) {
      print('result count: $previous -> $next');
    },
  );
});

Use a scope when the same screen, route, request, test, or temporary workflow creates several reactions and later disposes them together.

Add Plain Dart Cleanup

If code inside the scope opens a stream subscription, controller, or other Dart resource, register cleanup explicitly:

_scope.run(() {
  final subscription = events.listen(print);
  onScopeDispose(subscription.cancel);
});

EffectScope groups Jolt reactions. onScopeDispose() lets ordinary resources use the same cleanup point.

Detached Work

detach: true keeps an effect out of the current scope:

final appStateLogger = Effect(
  () => print(appState.value),
  detach: true,
);

Use it only when code outside the current scope will dispose that effect:

appStateLogger.dispose();

Do not create reactions and leave their lifecycle implicit. If you store an Effect or Watcher in a field, dispose that field. If you create reactions inside scope.run(), dispose the scope.

Next Step

Connect the same model to batches, streams, async state, persistence, and narrower read surfaces in Advanced Techniques.

Classes

EffectScope

A disposal boundary that groups effects, signals, and scope cleanups.