return an observable correct-CodePudding

I followed the last hours a tutorial about jwt refresh tokens but it seems that the code is a bit older and there were some changes. So I build an interceptor which got a problem with the Observable and I don't know how to fix it.

The Error is:

"Function lacks ending return statement and return type does not include 'undefined'"

and I know it shows up because my Observable has no specific return.

My Code:

intercept(request : HttpRequest<any>, next : HttpHandler): Observable<HttpEvent<any>> 
    {
        // Check if the user is logging in for the first time

        return next.handle(this.attachTokenToRequest(request)).pipe(
            tap((event : HttpEvent<any>) => {
                if(event instanceof HttpResponse) 
                {
                    console.log("Success");
                }
            }),
            catchError((err) : Observable<any> => { //Here comes the error message
                if(err instanceof HttpErrorResponse) {
                    switch((<HttpErrorResponse>err).status) 
                {
                        case 401:
                            console.log("Token expired. Attempting refresh ...");
                            return this.handleHttpResponseError(request, next);
                        case 400:
                            return <any>this.acct.logout();
                    }
                } else 
                {
                    return throwError(this.handleError);
                }
                //I think here should be a return but I don't know which kind, tried already a few ones
            })
            
           );

    }

I also can show you the original Code of the tutorial, that's the link:

https://dev.azure.com/Techhowdy/_git/NG_Core_AuthRTDB?path=/ClientApp/src/app/_helpers/jwt.Interceptor.ts

CodePudding user response：

Catches errors on the observable to be handled by returning a new observable or throwing an error. catchError

  intercept(request: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
    // Check if the user is logging in for the first time

    return next.handle(this.attachTokenToRequest(request)).pipe(
      tap((event: HttpEvent<any>) => {
        if (event instanceof HttpResponse) {
          console.log('Success');
        }
      }),
      catchError((err): Observable<any> => {
        if (err instanceof HttpErrorResponse && err.status === 401) return this.handleHttpResponseError(request, next);

        /**
         * I think the problem is here, the logout function does not return an observable and you can do like this
         */
        if (err instanceof HttpErrorResponse && err.status === 400) this.acct.logout();

        return throwError(this.handleError);
      }),
    );
  }