Used as a NON-CANCELLABLE means of subscribing to an observable, for use with APIs that expect promises, like async/await. You cannot unsubscribe from this.

WARNING: Only use this with observables you know will complete. If the source observable does not complete, you will end up with a promise that is hung up, and potentially all of the state of an async function hanging out in memory. To avoid this situation, look into adding something like {@link timeout}, {@link take}, {@link takeWhile}, or {@link takeUntil} amongst others.

Example

import { interval, take } from 'rxjs';

const source$ = interval(1000).pipe(take(4));

async function getTotal() {
  let total = 0;

  await source$.forEach(value => {
    total += value;
    console.log('observable -> ' + value);
  });

  return total;
}

getTotal().then(
  total => console.log('Total: ' + total)
);

// Expected:
// 'observable -> 0'
// 'observable -> 1'
// 'observable -> 2'
// 'observable -> 3'
// 'Total: 6'

Creates a new Observable, with this Observable instance as the source, and the passed operator defined as the new observable's operator.

Creates a new Observable by calling the Observable constructor