google maps API javascript v3 - polyline snap to road

snaptoroad.js

var directionsService = new google.maps.DirectionsService();


directionsService.route(request, function (response, status) {
if (status == google.maps.DirectionsStatus.OK) {
               
                var polyline = new google.maps.Polyline(polylineOptions);
                var path = response.routes[0].overview_path;
                for (var x in path) {
                    polyline.getPath().push(path[x]);
                }
                polyline.setMap(map);
                polylines.push(polyline);
        }
}