Observable<T>.switchLatest constructor

  1. Stream<Stream<T>> streams

Convert a Stream that emits Streams (aka a "Higher Order Stream") into a single Observable that emits the items emitted by the most-recently-emitted of those Streams.

This Observable will unsubscribe from the previously-emitted Stream when a new Stream is emitted from the source Stream and subscribe to the new Stream.


final switchLatestStream = new SwitchLatestStream<String>(
  new Stream.fromIterable(<Stream<String>>[
    new Observable.timer('A', new Duration(seconds: 2)),
    new Observable.timer('B', new Duration(seconds: 1)),
    new Observable.just('C'),

// Since the first two Streams do not emit data for 1-2 seconds, and the
// 3rd Stream will be emitted before that time, only data from the 3rd
// Stream will be emitted to the listener.
switchLatestStream.listen(print); // prints 'C'


factory Observable.switchLatest(Stream<Stream<T>> streams) =>