Angular 8 在异步调用链之后返回可观察的

Question

I have a simple function that calls 3 async functions one after another like this:

getData() {
    this.getUsers('2')
        .pipe(
        flatMap((data: any) => {  
            return this.getPosts(data.id);
        }),
        flatMap((data: any) => {            
            return this.getPosts(data[0].userId);
        })
        ).subscribe(results => {    
        return new Observable((observer) => {
        observer.next(results);
        observer.complete();
        });
    });
}

I would like someway to be able to call something like: this.getdata.subscribe() and that be called when all 3 flatMaps are completed. I assume I would have to have the getData() function return an observable which I tried to do at the bottom but it does not work and I am not able to call .subscribe on the getData() function.

Answer 1

Try like this:

Working Demo

getData() {
    return this.getUsers('2')
      .pipe(
        flatMap((data: any) => {  
          return this.getPosts(data.id);
        }),
        flatMap((data: any) => {            
          return this.getPosts(data[0].userId);
        })
      )
  }