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forkJoin

Alternatives: allWithNotifications, allN

Types​

function forkJoin<GObservables extends IGenericForkInObservables>(
  observables: GObservables,
): IObservable<IForkJoinObservableNotifications<GObservables>

Definition​

Waits for the first observable to send an error Notification, or all observables sending a complete Notification.

If it received an error Notification, it will send this error Notification.

If it received only complete Notifications, it will emit an array with the last values received through the next Notifications for each observable, followed by a complete Notification.

This is equivalent of Promise.all.

Diagrams​

If all completed​

If one errored​

Example​

Example 1​

const observable1$ = singleN(false);
const observable2$ = switchMap$$(timeout(2000), () => singleN(true)); // emits 'true' after 2000ms

const result$ = forkJoin([observable1$, observable2$]);

result$((notification) => {
  console.log(notification.name, notification.value);
});

Output:

// t = 2000ms
'next', [false, true]
'complete', undefined