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raceWithNotifications

Alternative: raceN

Types​

function raceWithNotifications<GObservables extends IGenericRaceInObservables>(
  observables: GObservables,
): IObservable<IRaceObservableNotifications<GObservables>>

Definition​

Waits for the first observable to send a complete or error Notification.

If it received a complete Notification, it will emit the last value received through the next Notifications of this observable, followed by a complete Notification.

If it received an error Notification, it will immediately send this Notification (error).

This is equivalent of Promise.race.

Diagrams​

If one completes​

OUTraceWithNotifications([observablesA, observablesB])observablesBobservablesAOUTraceWithNotifications([observablesA, observablesB])observablesBobservablesAnext: b1next: a1completenext: a1complete

If one errored​

OUTraceWithNotifications([observablesA, observablesB])observablesBobservablesAOUTraceWithNotifications([observablesA, observablesB])observablesBobservablesAnext: b1error: errorAerror: errorA

Example​

Select the first Observable to complete​

const observable1$ = switchMap$$(timeout(500), () => singleN<'a1'>('a1'));
const observable2$ = switchMap$$(timeout(1000), () => singleN<'a2'>('a2'));

const subscribe = raceWithNotifications([observable1$, observable2$]);

subscribe((value: IDefaultNotificationsUnion<'a1' | 'a2'>) => {
  console.log(value);
});

Output:

// t = 500ms
'next', 'a1'
'complete', undefined