signals.dart

final counter = signal(0);
final userProfile = signal({ 'name': 'Guest' });
final counterSquared = computed((context) {
  final count = context.watch(counter);
  return count * count;
})

final printEffect = effect((context) {
  final count = context.watch(counter);
  print('Counter changed to $count');
});

counterSquared.dispose();
printEffect.dispose();

final transaction = SignalTransaction()..addAll([counter, userProfile]);
transaction.add(counter);
counter.value = 5;
userProfile.value = { 'name': 'Alice' };
transaction.commit();

class Foo extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Text('Count: ${context.watch(counter)}');
  }
}

// https://github.com/brianegan/flutter_architecture_samples/blob/d898d1329e04e5b5fbdef1285b39ef975a6b8efa/signals/lib/todo_list_controller.dart#L4
class TodoModel {
  ListSignal<Todo> todos = signal([]);

  ReadonlyListSignal<Todo> get completedTodos => computed((context) {
    return context.watch(todos).where((todo) => todo.isCompleted).toList();
  });
}