Create Observable from async generator

async_generator_to_observable.ts

this.obs = createFrom(async function *() {
      await delay(1000);
      yield 1;
      yield 2;
      await delay(500);
      await delay(300);
      yield 3;
      await delay(400);
      yield 4;
      yield 5;
      await delay(1000);
      yield 6;
      return;
    });

function createFrom<T>(asyncCollection: () => AsyncIterableIterator<T>): Observable<T> {
  return new Observable<T>(subscriber => {
    (async () => {
      try {
        for await (const value of asyncCollection()) {
          subscriber.next(value);
        }
        subscriber.complete();
      } catch (err) {
        subscriber.error(err);
      }
    })();
  });
}