order-api.service.ts

public orderPost(offerId: string, takeaway: boolean): Observable<Order> {

        //http call prep code ...
        //...
  
        let obs = this.http.post(path, orderBooking, requestOptions)
            .map((response: Response) => {
                if (response.status === 204) {
                    return undefined;
                } else {
                    return response.json();
                }
            })
            .publish(); //ensuring we only have one subscription to pass around, otherwise you get multiple http calls every time
        obs.connect();  
        
        //here we tell the feedback service what we want. we'd like spinning and toasting
        this.vfeedback.showMessageOnAnswer('Order placed!', 'Oops', obs);
        this.vfeedback.spinUntilCompleted(obs);
        return obs;

    }