publishValue method

ValueConnectableObservable<T> publishValue ()

Convert the current Observable into a ValueConnectableObservable that can be listened to multiple times. It will not begin emitting items from the original Observable until the connect method is invoked.

This is useful for converting a single-subscription stream into a broadcast Stream that replays the latest emitted value to any new listener. It also provides access to the latest value synchronously.

Example

final source = Observable.fromIterable([1, 2, 3]);
final connectable = source.publishValue();

// Does not print anything at first
connectable.listen(print);

// Start listening to the source Observable. Will cause the previous
// line to start printing 1, 2, 3
final subscription = connectable.connect();

// Late subscribers will receive the last emitted value
connectable.listen(print); // Prints 3

// Can access the latest emitted value synchronously. Prints 3
print(connectable.value);

// Stop emitting items from the source stream and close the underlying
// BehaviorSubject
subscription.cancel();

Implementation

ValueConnectableObservable<T> publishValue() =>
    ValueConnectableObservable<T>(this);