Handling Expired Token From Api in Angular 4

Question

I need help in handling expired token in my angular application. My api has the expired time but my problem is when i forgot to log out of my angular application, after some tim

Answer 1

You can do this using http interceptors.

intercept(req: HttpRequest, next: HttpHandler) {
  if(!localStorage.getItem('token'))
    return next.handle(req);

  // set headers
  req = req.clone({
    setHeaders: {
      'token': localStorage.getItem('token')
    }
  })

  return next.handle(req).do((event: HttpEvent) => {
    if(event instanceof HttpResponse){
      // if the token is valid
    }
  }, (err: any) => {
    // if the token has expired.
    if(err instanceof HttpErrorResponse){
      if(err.status === 401){
        // this is where you can do anything like navigating
        this.router.navigateByUrl('/login');
      }
    }
  });
}

Here's the full solution