Angular2 catch request error

Question

I have a code to get request. It's compiling and working but I have an error in console.

public get<T>(url: string, headers: Headers = this.jsonHeaders()): Observable<T> {
        return this._http.get(url, { headers: headers })
                   .catch((err: Response, caught: Observable<T>) => {
                       if (err.status === 401) {
                           this._router.navigate(["/auth/login"]);
                           return Observable.throw("401 Unauthorized");
                       }
                       return caught;
                   })
                   .map(res => <T>this.toJSON(res));
    }

error:

error TS2345: Argument of type '(err: Response, caught: Observable<T>) => ErrorObservable | Observable<T>' is not assignable to parameter of type '(err: any, caught: Observable<Response>) => Observable<any>'.
  Types of parameters 'caught' and 'caught' are incompatible.
    Type 'Observable<Response>' is not assignable to type 'Observable<T>'.
      Type 'Response' is not assignable to type 'T'.

I tried cast it to but it's not helped

see here to http://stackoverflow.com/a/37052710/5043867 – Pardeep Jain May 19 '16 at 08:31 — Pardeep Jain, May 19 '16 at 08:31

score 9 · Accepted Answer · answered May 19 '16 at 08:17

9

You use the following:

.catch((err: Response, caught: Observable<T>) => {
  if (err.status === 401) {
    this._router.navigate(["/auth/login"]);
    return Observable.throw("401 Unauthorized");
  }
  return Observable.throw(caught); // <-----
})

answered May 19 '16 at 08:17

Thierry Templier

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That is work fine but I still have an error in console. – Illorian May 19 '16 at 08:31
Could you try: `return caught.source;`? – Thierry Templier May 19 '16 at 08:33
1

I think reason is that expected Observable but return ErrorObservable – Illorian May 19 '16 at 08:41
Yes agreed but the `source` property of the `ErrorObservable` contains the source observable of type `Observable`. So it should fix the problem ;-) – Thierry Templier May 19 '16 at 08:44
But it's not =( Maybe because caught hasn't source property – Illorian May 19 '16 at 08:46
In the case of an error other than 401, you want to throw the source error? If so, you could try `Observable.throw(err);`. – Thierry Templier May 19 '16 at 08:51
I'd like prevent other actions if something catches but I don't think that it's possible – Illorian May 19 '16 at 08:56

Angular2 catch request error

1 Answers1