Stream Bindings

Bind streams to state holders with automatic subscription management.

late final user = bind(repo.userStream, initial: null);
// Subscription auto-cancels on ViewModel dispose

bind()

Bind a stream directly to a StateHolder:

class AuthViewModel extends ViewModel {
  late final user = bind(repo.userStream, initial: null);
}

When the stream emits, user.value updates automatically.

With Transform

late final user = bind(
  repo.userStream,
  initial: null,
  transform: (u) => u?.copyWith(name: u.name.toUpperCase()),
);

stateFrom()

Bind with type transformation:

late final isLoggedIn = stateFrom<User?, bool>(
  repo.userStream,
  initial: false,
  transform: (user) => user != null,
);

Creates StateHolder<bool> from Stream<User?>.

bindAsync()

Bind to AsyncStateHolder with loading/error handling:

late final todos = bindAsync(repo.watchAll());

• Starts in AsyncLoading
• Transitions to AsyncData on emit
• Transitions to AsyncError on error

subscribe()

For custom handling:

class ChatViewModel extends ViewModel {
  late final messages = state<List<Message>>([]);
  late final unreadCount = state(0);

  ChatViewModel(ChatRepository repo) {
    subscribe(
      repo.messagesStream,
      (msgs) {
        messages.value = msgs;
        unreadCount.value = msgs.where((m) => !m.read).length;
      },
      onError: (e) => error.value = e.toString(),
    );
  }
}

API Summary

Method	Output	Use Case
bind()	StateHolder<T>	Direct binding
stateFrom()	StateHolder<R>	Type transform
bindAsync()	AsyncStateHolder<T>	With loading/error
subscribe()	void	Custom handling