@Injectable()
export class EmptyResponseInterceptor implements HttpInterceptor {

  intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
    const newReq = req.clone({
      responseType: 'text'
    });

    return next.handle(newReq).map((event: HttpEvent<any>) => {
      if (event instanceof HttpResponse) {
        let newEvent: HttpEvent<any>;

        // alter response here. maybe do the following
        newEvent = event.clone({
          // alter event params here
        });

        return newEvent;
      }
    });
  }
}

(res:HttpResponse<any>) => console.log(res.body.json)