switchMap 到 switchMapTo

Question

目前我有这段代码

this.save()
  .pipe(switchMap(() => this.unlock()))
  .subscribe(...);

save和unlock实现是

private save(): Observable<void> {
  return new Observable(subscriber => {
    this.xmlService.save(..., () => {
      ...       
      subscriber.next();
      subscriber.complete();
    });
  });
}

private unlock(): Observable<void> {
  return this.httpService.unlock(this.id);
}

---

由于这unlock并不真正依赖于值save返回，我可以使用吗switchMapTo？

this.save()
  .pipe(switchMapTo(this.unlock()))
  .subscribe(...);

或者我误解了*To变体的行为方式？

Answer 1

switchMapTo与 相同，switchMap只是它采用可观察值而不是回调函数。查看源代码：

https://github.com/ReactiveX/rxjs/blob/master/src/internal/operators/switchMapTo.ts#L56