Empty Array In Callback

I am using geocoder npm module to convert the address to lat,long. This API reads address from file google.csv using fast csv npm module after that result i.e addresses are passed

Solution 1:

You'll want to use async.parallel. Since you are calling multiple geocoder.geocode. Since it is asynchronous, your function returns a value before they have ended.

functiongetLatLong(responseObj, callback){
    var responseArray = responseObj.adrressarray; 
    var geocodeArray  = responseArray.Success.slice(1);
    var geoLatLongFunctions   = geocodeArray.map(function(x) {
        returnfunction(cb){
            var addressOfRow = x.toString();
            geocoder.geocode(addressOfRow, function (err, data) {
                if(err){
                     cb(err);
                }
                var latitude    = data.results[0].geometry.location.lat;
                var longitude   = data.results[0].geometry.location.lng;
                var address     = data.results[0].formatted_address;
                var obj         = [{"latitude":latitude,"longitude":longitude, "address":address}];
                cb(null,obj);
            });
         };
    }); 
    async.parallel(geoLatLongFunctions,callback);
}

Here, what I've done is make your geocodeArray.map return a function instead. And used async.parallel to execute them. Once all of them has finished, the callback will be called containing the results of all executions.

Solution 2:

You are calling the callback too soon (synchronously), while the array is only populated later (asynchronously).

Make these changes:

functiongetLatLong(responseObj, callback){
    var latlongArray = []; // Define & initialise array here!var responseArray = responseObj.adrressarray; 
    var geocodeArray  = responseArray.Success.slice(1);
    geocodeArray.map(function(x) {
        var addressOfRow = x.toString();
        geocoder.geocode(addressOfRow, function (err, data) {
            if(err){
                returncallback(err);
            }
            var latitude    = data.results[0].geometry.location.lat;
            var longitude   = data.results[0].geometry.location.lng;
            var address     = data.results[0].formatted_address;
            var obj         = [{"latitude":latitude,"longitude":longitude, "address":address}];
            latlongArray.push(obj);
            // Only call callback when array is completeif (latlongArray.length == geocodeArray.length) {
                callback(null, latlongArray);
            }
        })
    }); 
}