Question

I am using javascript, google direction service
I have multiple source points on the map and one destination point. I need to find the closest source point to the destination point. As direction service works asynchronously I need to map points with their lat/lang. However the problem is that, the response format sent by direction service changes.

    function calcRoute(start, end) {
    var request = {
        origin:start,
        destination:end,
        travelMode:google.maps.DirectionsTravelMode.DRIVING
    };

    directionsService.route(request, 
        function (response, status) {
            distanceCount++;
            if (status == google.maps.DirectionsStatus.OK) {                    
                var dist = computeTotalDistance(response);
                console.log(dist);
                if (dist < minDistance) {
                    minDistance = dist;
                    minDistanceIndex = locationsMap[response.ug.origin.Ua+""+response.ug.origin.Va];
                }
                if (distanceCount == vl.length) {
                    drawWay(vl[minDistanceIndex], fsl);
                }
            }
        }
    );
}

The problem occurs on the line

minDistanceIndex = locationsMap[response.ug.origin.Ua+""+response.ug.origin.Va];

response.ug.origin.Va and response.ug.origin.Ua comes from google direction service, however it sometimes changes to response.ug.origin.Xa and response.ug.origin.Ya.

Do you have any ideas why it changes from time to time? or any ideas how to deal with that problem?

Answer 1

You don’t have to access those internal properties, they are not a part of the API so they may change.

Use only the properties/methods defined inside the specification, all data provided by the response are accessible through them,

example:

response.routes[0].legs[0].start_location
//returns latLng of the origin

Apart from that:

Your description sounds as if you better should use a DistanceMatrixRequest