auth-rejector.interceptor.ts

import 'rxjs/add/operator/map';

export class JwtInterceptor implements HttpInterceptor {

  constructor(public auth: AuthService) {}

  intercept(request: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
    
    return next.handle(req).map((event: HttpEvent<any>) => {
      if (event instanceof HttpResponse) {
        // do stuff with response if you want
      }
    }, (err: any) => {
      if (err instanceof HttpErrorResponse {
        if (err.status === 401) {
          // redirect to the login route
          // or show a modal
        }
      }
    });
  }
}