Assaf Azulai's example for rxjs post

handleError.ts

interactionSubject = new Subject<void>();
ngOnInit() {
  this.interactionSubject.asObservable().pipe(
    switchMap((data) => {
      this.server.fetchData(data).pipe(
        catchError((err) => {
          // handle error
        })
      )
    })
  ).subscribe(dataFromServer => {
    // Do something
  });
}
interaction1() {
  this.interactionSubject.next();
}
interaction2() {
  this.interactionSubject.next();
}