How to cancel current request in interceptor - Angular 4

Question

As you know it\'s possible to use Interceptors in new versions of Angular 4.

In mine, I want to cancel a request in interceptor in some conditions. So i

Answer 1

Inspired by @RVP answer I have found out that it's possible to cut the chain with an error in the same simple way using Observable.throw()

//...
intercept(req: HttpRequest, next: HttpHandler): Observable> {
    if (stopThisRequestWithError) {
        return Observable.throw('Error message');
    } else {
        return next.handle(req);
    }
}

This avoids fulfilling response promises with undefined values.