Observable<T>.periodic constructor

Observable<T>.periodic(Duration period, [ T computation(int computationCount) ])

Creates an Observable that repeatedly emits events at period intervals.

The event values are computed by invoking computation. The argument to this callback is an integer that starts with 0 and is incremented for every event.

If computation is omitted the event values will all be null.


 new Observable.periodic(new Duration(seconds: 1), (i) => i).take(3)
   .listen(print); // prints 0, 1, 2


factory Observable.periodic(Duration period,
        [T computation(int computationCount)]) =>
    new Observable<T>((new Stream<T>.periodic(period, computation)));