combineLatestAll

function stable

Flattens an Observable-of-Observables by applying combineLatest when the Observable-of-Observables completes.

`combineLatestAll<R>(project?: (...values: any[]) => R)`

Parameters

project

Optional. Default is undefined.

optional function to map the most recent values from each inner Observable into a new result. Takes each of the most recent values from each collected inner Observable as arguments, in order.

Description

combineLatestAll takes an Observable of Observables, and collects all Observables from it. Once the outer Observable completes, it subscribes to all collected Observables and combines their values using the combineLatest strategy, such that:

Every time an inner Observable emits, the output Observable emits
When the returned observable emits, it emits all of the latest values by:
- If a project function is provided, it is called with each recent value from each inner Observable in whatever order they arrived, and the result of the project function is what is emitted by the output Observable.
- If there is no project function, an array of all the most recent values is emitted by the output Observable.

Examples

Map two click events to a finite interval Observable, then apply `combineLatestAll`

import { fromEvent, interval } from 'rxjs';
import { map, combineLatestAll, take } from 'rxjs/operators';

const clicks = fromEvent(document, 'click');
const higherOrder = clicks.pipe(
  map(ev =>
     interval(Math.random() * 2000).pipe(take(3))
  ),
  take(2)
);
const result = higherOrder.pipe(
  combineLatestAll()
);

result.subscribe(x => console.log(x));

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