如何迭代返回rxjs可观察值的函数？

import { Observable } from 'rxjs';

function* iterateObservable(): IterableIterator<Observable<number>> {
  yield new Observable<number>(observer => {
    observer.next(1);
    observer.next(2);
    observer.next(3);
    observer.complete();
  });

  yield new Observable<number>(observer => {
    observer.next(4);
    observer.next(5);
    observer.next(6);
    observer.complete();
  });
}

const iterator = iterateObservable();

function getNextObservable(): Observable<number> {
  const { value, done } = iterator.next();
  if (done) {
    return null;
  }
  return value;
}

// 使用getNextObservable函数来获取下一个可观察值
const observable1 = getNextObservable();
observable1.subscribe(value => console.log(value));

const observable2 = getNextObservable();
observable2.subscribe(value => console.log(value));

const observable3 = getNextObservable();
observable3.subscribe(value => console.log(value));