Multicast Operator with Pipe in RxJS 5.5+

Question

How do I use the multicast() operator with the new recommended approach in RxJS 5.5 of using pipe() instead of chaining operators? I get a TypeScript error when I try to use connect() like I did before:

const even$ = new Subject();

const connectedSub = interval(500)
    .pipe(
        filter(count => count % 2 === 0),
        take(5),
        multicast(even$)
    )
    .connect();

even$.subscribe(value => console.log(value));

This code works but yields a TypeScript error that reports that Property 'connect' does not exist on type 'Observable<{}>'. Am I using connectable observables the way that I should be in RxJS 5.5+?

cartant cartant · Accepted Answer · 2018-05-04T02:47:17

The current - v5.5.10 and v6.1.0 - typings for pipe are not aware of the Observable subclasses, so I use a type assertion, like this:

const connectedObs = interval(500).pipe(
    filter(count => count % 2 === 0),
    take(5),
    multicast(even$)
) as ConnectableObservable<number>;
const connectedSub = connectedObs.connect();

Multicast Operator with Pipe in RxJS 5.5+

1 Answers