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Asked: 2026-06-15T23:40:59+00:00

Iam having some problems with a function I wrote. I want to wrap this

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Iam having some problems with a function I wrote.
I want to wrap this whole thing into a function called myClosestCity that returns the name of the city based on a JSON feed that gives coordinates from users IP. As far as I can see the problem is within the getJSON function.
I’ve tried with global variables, getters and setters (which didnt work at all) and just about everything I could think of Googling.

By the way, for the code to run you’ll need to include a script from Google Maps:
http://maps.google.com/maps/api/js?sensor=false&libraries=geometry

Anyway, here’s my whole code:

var stavanger = new google.maps.LatLng(58.96998, 5.73311);
var oslo = new google.maps.LatLng(59.91387, 10.75225);
var trondheim = new google.maps.LatLng(63.43051, 10.39505);
var bergen = new google.maps.LatLng(60.39126, 5.32205);

function calcDistance(p1, p2){
  return (google.maps.geometry.spherical.computeDistanceBetween(p1, p2) / 1000).toFixed(2);
}



$.getJSON("http://www.geoplugin.net/json.gp?jsoncallback=?", function(data) {
myLocation = new google.maps.LatLng(data.geoplugin_latitude,data.geoplugin_longitude);
var distances = new Array();
distances[0] = calcDistance(myLocation, stavanger);
distances[1] = calcDistance(myLocation, oslo);
distances[2] = calcDistance(myLocation, trondheim);
distances[3] = calcDistance(myLocation, bergen);



maxValue = Math.min.apply(this, distances);
var findThisIndex = maxValue + "";
var placeNo = $.inArray(findThisIndex, distances);


if(placeNo == 0) {
    closestCity = "Stavanger";
}

else if (placeNo == 1){
    closestCity = "Oslo";
}

else if(placeNo == 2) {
    closestCity = "Trondheim";
}

else if(placeNo == 3){
    closestCity = "Bergen";
}

else {
    closestCity = "Ukjent"; // Unknown in Norwegian
}

alert(closestCity);
  });

Update: It’s the closestCity variable I’d like to return!

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1 Answer

  1. Editorial Team

    You can define your function and then wait for server response, then use your closestCity.
    You cand modify your code in this way:

    var myClosestCity = function(callback) {
    var stavanger = new google.maps.LatLng(58.96998, 5.73311);
    var oslo = new google.maps.LatLng(59.91387, 10.75225);
    var trondheim = new google.maps.LatLng(63.43051, 10.39505);
    var bergen = new google.maps.LatLng(60.39126, 5.32205);

    function calcDistance(p1, p2) {
        return (google.maps.geometry.spherical.computeDistanceBetween(p1,      p2) / 1000).toFixed(2);
    }


    $.getJSON("http://www.geoplugin.net/json.gp?jsoncallback=?", function(data) {
        myLocation = new google.maps.LatLng(data.geoplugin_latitude, data.geoplugin_longitude);
        var distances = [];
        distances[0] = calcDistance(myLocation, stavanger);
        distances[1] = calcDistance(myLocation, oslo);
        distances[2] = calcDistance(myLocation, trondheim);
        distances[3] = calcDistance(myLocation, bergen);



        maxValue = Math.min.apply(this, distances);
        var findThisIndex = maxValue + "";
        var placeNo = $.inArray(findThisIndex, distances);


        if (placeNo === 0) {
            closestCity = "Stavanger";
        }

        else if (placeNo == 1) {
            closestCity = "Oslo";
        }

        else if (placeNo == 2) {
            closestCity = "Trondheim";
        }

        else if (placeNo == 3) {
            closestCity = "Bergen";
        }

        else {
            closestCity = "Ukjent";
        }

        if (typeof callback === "function") {
            callback.call(null, closestCity);
        }
    });
};


//call the function and display the closestCity on callback
myClosestCity(function(closestCity) {
    alert(closestCity);
});?
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