mergeWith

Merge the values from all observables to an single observable result.

mergeWith<T, A extends readonly unknown[]>(...otherSources: any[]): OperatorFunction<T, T | A[number]>

Parameters

Returns

OperatorFunction<T, T | A[number]>: A function that returns an Observable that merges the values from all given Observables.

Description

Creates an observable, that when subscribed to, subscribes to the source observable, and all other sources provided as arguments. All values from every source are emitted from the resulting subscription.

When all sources complete, the resulting observable will complete.

When any one source errors, the resulting observable will error.

Example

Joining all outputs from multiple user input event streams:

import { fromEvent } from 'rxjs';
import { map, mergeWith } from 'rxjs/operators';

const clicks$ = fromEvent(document, 'click').pipe(map(() => 'click'));
const mousemoves$ = fromEvent(document, 'mousemove').pipe(map(() => 'mousemove'));
const dblclicks$ = fromEvent(document, 'dblclick').pipe(map(() => 'dblclick'));

mousemoves$.pipe(
  mergeWith(clicks$, dblclicks$),
)
.subscribe(x => console.log(x));

// result (assuming user interactions)
// "mousemove"
// "mousemove"
// "mousemove"
// "click"
// "click"
// "dblclick"