Uncaught Exception When Calling Google Maps DirectionsService

I am getting an Uncaught InvalidValueError: in property origin: not a string; and not a LatLng or LatLngLiteral: not an Object error when I call the Google maps directions service

Solution 1:

Your currentPos variable is undefined when you call calcRoute.
getCurrentPosition is asynchronous and will not have executed before calcRoute and therefore not set currentPos.
If you need to use currentPos in calcRoute you should call it in the callback to getCurrentPosition to ensure that it is defined.

if (navigator.geolocation) {
    navigator.geolocation.getCurrentPosition(function (position) {
        currentPos = new google.maps.LatLng(position.coords.latitude,
                                         position.coords.longitude);

        var marker = new google.maps.Marker({
            position: currentPos,
            map: map,
            title: "You are here"
        });

        marker.setIcon('http://maps.google.com/mapfiles/ms/icons/green-dot.png')

        map.setCenter(currentPos);

        $.ajax({
            type: 'GET',
            url: $('#AddMarkersToMap').val(),
            contentType: "application/json; charset=utf-8",
            dataType: "json",
            success: function (data) {
                addMarkers(data, infoWindow);
            },
            error: function () {
                alert("Error");
            }
        });
        calcRoute();
        //\\//\\//\\
    }, function () {
        handleNoGeolocation(true);
    });