publishState method

StateConnectableStream<T> publishState(
  1. T seedValue, {
  2. Equality<T>? equals,
  3. bool sync = true,
})

Convert the this Stream into a StateConnectableStream that can be listened to multiple times, providing an initial seeded value. It will not begin emitting items from the original Stream until the connect method is invoked.

This is useful for converting a single-subscription stream into a broadcast Stream, that also provides access to the latest value synchronously.

Example

final source = Stream.fromIterable([1, 2, 2, 3, 3, 3]);
final connectable = source.publishState(0);

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

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

// Late subscribers will not receive anything
connectable.listen(print);

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

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

Implementation

StateConnectableStream<T> publishState(
  T seedValue, {
  Equality<T>? equals,
  bool sync = true,
}) =>
    StateConnectableStream<T>(this, seedValue, equals: equals, sync: sync);