google-map-test-direction.js

(function(global) {
    var google = global.google;
    var directionsService = new google.maps.DirectionsService();
    var directionsDisplay;

    // initialize google map
    var initialize = function() {
        var mapOptions = {
            center: new google.maps.LatLng(-34.397, 150.644),
            zoom: 5,
            mapTypeId: google.maps.MapTypeId.ROADMAP
        };

        // initialize map
        var map = new google.maps.Map(document.getElementById("map-canvas"), mapOptions);

        directionsDisplay = new google.maps.DirectionsRenderer();
        directionsDisplay.setMap(map);


        // add event on map click
        // @param {Object} event The custom map event object
        // which contain latitude and langitude
        google.maps.event.addListener(map, 'click', function(event) {
            // getUserPosition is async function
            // because it require user permission
            getUserPosition(calcRoute.bind(global, event.latLng));
        });
    };

    // html 5 geolocation API
    // Get user position
    var getUserPosition = function(callback) {
        global.navigator.geolocation.getCurrentPosition(function(position) {
            var latitude = position.coords.latitude;
            var langitude = position.coords.longitude;
            // convert user position to google.maps
            // LatLng object
            var origin = new google.maps.LatLng(latitude, langitude);

            callback(origin);
        } /*, onError */ );
    };

    // calc direction from user location
    // to position clicked on map
    var calcRoute = function(distPosition, originPosition) {

        var request = {
            origin: originPosition,
            destination: distPosition,
            travelMode: google.maps.TravelMode.DRIVING // it's work onliy for one continent
        };

        directionsService.route(request, function(result, status) {
            if (status === google.maps.DirectionsStatus.OK) {
                directionsDisplay.setDirections(result);
            }
        });
    };

    // events
    google.maps.event.addDomListener(window, 'load', initialize);
}(this));