Calling Async method inside Foreach loop JS

Question

I'm trying to make a Async call to Google Maps for address inside a foreach loop.

This is the function:

//Function to get address from geographic coordinates
        function getAddress(item) {
            var address = 'Not fetched';
            geocoder = new google.maps.Geocoder();
                var latlng = new google.maps.LatLng(parseFloat(item.Latitude), parseFloat(item.Longitude));
                geocoder.geocode({ 'latLng': latlng }, function (results, status) {
                    if (status == google.maps.GeocoderStatus.OK)
                        address = results[0].formatted_address;
                });
                return address;
        }

This is the loop:

 recreateMarkers: function (self, data) {
                        data.vehicleInfo.forEach(function (item) {
                            self.Location= getAddress(item);
                        });
                    }

Structure of Data: 1. VehicleId 2. Latitude 3. Longitude 4. Location

Now the problem is it gives me same or undefined location for all vehicles.

Would be glad if someone can assist.

This wouldn't even work without the loop. – Bergi Aug 15 '14 at 12:28 — Bergi, Aug 15 '14 at 12:28

Suman Bogati · Answer 1 · 2014-08-15T12:43:35.377

Here is the problem of asynchronous ,

return address is executed before google fetched address is assigned by address = results[0].formatted_address; so your function should be something like this

 function getAddress(item) {
            var address = 'Not fetched';
            geocoder = new google.maps.Geocoder();
                var latlng = new google.maps.LatLng(parseFloat(item.Latitude), parseFloat(item.Longitude));
                geocoder.geocode({ 'latLng': latlng }, function (results, status) {
                    if (status == google.maps.GeocoderStatus.OK)
                        address = results[0].formatted_address;
                        return address; //<= this statement should be here
                });
           // Note return address; should not be here
    }

I tried this. Still it says undefined. – Ashish Charan Aug 15 '14 at 12:27 — Ashish Charan, Aug 15 '14 at 12:27

Calling Async method inside Foreach loop JS

1 Answers1