Angular 2 rxjs FlatMap error

Question

I have following method :

request(url: string|Request, options?: RequestOptionsArgs): Observable<Response> {
    this.customOptions = options;
    return this.authService.approveTokenExpiration()
      .flatMap((res) => {
        if (!(res.json().data.error) && !(res.error)) {
          console.log("addedHeaders");
          this.addAuthHeader();
          console.log(this.customOptions);
        } else {
          // return this.authService.refreshToken()
          //   .flatMap(() => {
          //     this.addAuthHeader();
          //     return super.request(url, this.customOptions);
          //   });
        }
      })
      .flatMap(res => {
        return super.request(url, this.customOptions);
      });
  }

and approveTokenExpiration method:

  public approveTokenExpiration(): Observable<any> {
    let header = new Headers();
    header.append('Authorization', this.formTokenHeaderValue());
    console.log(header);
    let options = new RequestOptions({headers: header});
    return this.http.get(Constants.SERVER_URL, options)
      .map(res => {
        return res;
      })
      .catch(err => {
        return err;
      });
  }

I'm getting such error when i'm trying to chain my rxjs requests:

ERROR in [at-loader] ./src/app/auth/intercept/auth.interceptor.ts:18:16 TS2345: Argument of type '(res: any) => void' is not assignable to parameter of type '(value: any, index: number) => ObservableInput<{}>'. Type 'void' is not assignable to type 'ObservableInput<{}>'.

How to chain this request properly? Do FlatMap chain both .map() and .error() methods? Can i chain requests in this way? Because i need to return Observable from my request method (its custom Http implementation) to let users .subscribe on this.

Robin Dijkhof Robin Dijkhof · Accepted Answer · 2017-06-25T19:45:03

.flatMap((res) => {
    if (!(res.json().data.error) && !(res.error)) {
      console.log("addedHeaders");
      this.addAuthHeader();
      console.log(this.customOptions);
    }

Your if statement is not returning a observable. You should return some observable here.

Angular 2 rxjs FlatMap error

1 Answers