mergeAll

signature: mergeAll(concurrent: number): Observable

Example 1: mergeAll with promises

Example 2: mergeAll with concurrent parameter

import { take, map, delay, mergeAll } from 'rxjs/operators';
const source = interval(500).pipe(take(5));
/*
  interval is emitting a value every 0.5s.  This value is then being mapped to interval that
  is delayed for 1.0s.  The mergeAll operator takes an optional argument that determines how
  many inner observables to subscribe to at a time.  The rest of the observables are stored
const example = source
  .pipe(map(val => source.pipe(delay(1000), take(3))), mergeAll(2))
  .subscribe(val => console.log(val));
/*
  The subscription is completed once the operator emits all values.

Additional Resources

• Flatten a higher order observable with mergeAll in RxJS
  - André Staltz