Question

I’m looking for a way to trigger user geolocation navigator function from another function mapInit(). It nearly works, but I can’t have a proper callback of getCurrentPosition() to confirm it went well.. it return undefined each times.

My geolocation object will have to achieve other tasks so I don’t want it to trigger mapInit(). It should have to get user location, record it and return trueor false.. Any guess?

Thanks 🙂

// Get user current position, return true or false
//
var geolocation = {
    get: function() {
        if (alert(navigator.geolocation.getCurrentPosition(this.success, this.error, {
            enableHighAccuracy: true,
            maximumAge: 5000
        })) {
            return true;
        } else {
            return false;
        }
    },
    success: function(position) {
        this.last = position; // record last position
        return true;
    },
    error: function() {
        alert('code: ' + error.code + 'n' + 'message: ' + error.message + 'n')
        return false;
    },
    last: undefined,
}

// Initialize leaflet map and get user location if coords are undefined
//
var mapInit = function(latitude, longitude) {
    if (!latitude && !longitude) { // if no latlng is specified, try to get user coords
        if (geolocation.get()) {
            latitude = geolocation.last.coords.latitude;
            longitude = geolocation.last.coords.longitude;
        } else {
            alert('oups!');
        }
    }
    var map = L.map('map').setView([latitude, longitude], 15);
    L.tileLayer('http://{s}.tile.cloudmade.com/#APIKEY#/68183/256/{z}/{x}/{y}.png', {
        minZoom: 13,
        maxZoom: 16,
    }).addTo(map);
    var marker = L.marker([latitude, longitude]).addTo(map);
}

Answer 1

Not sure I understand what you’re trying to do but when you call “getCurrentPosition” the first argument you pass is a method that will be called with the Position once it is retrieved. As you said in your comment getCurrentPosition will always return immediately but the callback method will be called if the user position can be retrieved (it may never be called):

navigator.geolocation.getCurrentPosition( function(position) {
  var lat = position.coords.latitude;
  var lon = position.coords.longitude;
  //do something like recent the Map
});

You will need to create the Leaflet Map first with some default coordinates and then recenter the map with the coordinates provided to the callback method.