Google Maps, real-time route update

button for the user's current location with the following code

   initMap() {
        this.geolocation.getCurrentPosition({ maximumAge: 3000, timeout: 5000,
                enableHighAccuracy: true }).then((resp) => {
                this.mylocation = new google.maps.LatLng(resp.coords.latitude,
                        resp.coords.longitude);

        this.map = new google.maps.Map(this.mapElement.nativeElement, {
                zoom: 15,
                center: this.mylocation
      });
        this.directionsDisplay.setMap(this.map);
    });

        let watch = this.geolocation.watchPosition();
        watch.subscribe((data) => {
                this.deleteMarkers();
//guardo datos en firebase
        this.actuario.update({
                lat: data.coords.latitude,
                lng: data.coords.longitude
      });
        this.lat = data.coords.latitude;
        this.lng = data.coords.longitude;
        this.updatelocation = new google.maps.LatLng(data.coords.latitude, data.coords.longitude);
        //this.calculateAndDisplay_Route(data.coords.latitude,data.coords.longitude);
        let image = 'assets/imgs/blue-bike.png';
        this.addMarker(this.updatelocation, image);
        this.setMapOnAll(this.map);
    });

    }

button to generate route

     calculateAndDisplay_Route(){

    this.directionsService.route({
            origin:{lat:this.lat,lng:this.lng},
    destination: this.direccion,
            travelMode: 'DRIVING'
}, (response, status) => {
        if (status === 'OK') {
            this.directionsDisplay.setDirections(response);
        } else {
            window.alert('Directions request failed due to ' + status);
        }
    });