Retry API call when value is not there

Question

Is there a way to continuously poll my API until a value is retrieved (but stop when it fails)? Right now, it makes the call, but as there is nothing there at the time, it does not retry. I want the retries to continue unless the call fails.

Component

  ngOnInit(): void {
     this.getCurrentUser(this.uid);
  }

  getCurrentUser(uid: string) {
    this.userService.getUser(uid).then((user: IUser[]) => {
      if (user && user.length > 0) {
        this.user = user[0];
      }
    });
  }

Service

  getUser(uid: string): Promise<Object | IUser[]> {
    return this.firebaseService.generateToken().then((token: string) => {
      return this.httpClient
        .get(`${environment.apiBasePath}/users/${uid}`, {
          headers: { authorization: `Bearer ${token}` },
        })
        .toPromise();
    });
  }

Answer 1

Call the function again from within itself if there is no data being returned.

getCurrentUser(uid: string) {
    this.userService.getUser(uid)
      .then((user: IUser[]) => {
        if (user && user.length > 0) {
          this.user = user[0];
        } else {
          this.getCurrentUser(this.uid)
        }
      })
      .catch(error = console.error(error);
  }

Perhaps set a limit on how many times you want this to happen? Or set use a setTimeout on the recall (in the else clause) so that it doesn't happen too rapidly?