I'm attemping to modify a Javascript snippet to more efficiently get the user's current Zipcode. One problem that I am facing however is the lack of understanding around public functions. I am wondering if they are requried, and if they are not, then what would make the code cleaner and more efficient in terms of using or not using public.?


var geoLocateAddress = function () {
        var public = {};  
        public.init = function() {
        public.initEventHandlers = function() {
            console.log("Using your browser's GeoLocation API");
        public.loadAddressByGeolocation = function(position) {
            console.log("Your browser only returns Long/Lat");    
        public.loadAddressByLngLat = function(position){
            var data = {
                lat : position.coords.latitude,
                lng : position.coords.longitude
            var url = "http://ws.geonames.org/findNearestAddressJSON";
                url: url,
                dataType: 'jsonp',
                data: data,
                success: function(data, textStatus, xhr) {
                        zipCode: data.address.postalcode,
                error: function(xhr, textStatus, errorThrown) {
            return false;
        public.updateAddressFields = function(address) {
            console.log('Zip: ' + address.zipCode);
            console.log('Zip Logged');

        return public;
    } ();
  • \$\begingroup\$ What are you getting by making the internal functions here public and available on a global namespace? \$\endgroup\$
    – Bill Barry
    Jul 9, 2012 at 21:39
  • \$\begingroup\$ Are you asking what my purpose is for making them public? Or what am I getting as in what's the output? \$\endgroup\$
    – Charlie
    Jul 9, 2012 at 21:40
  • \$\begingroup\$ What is your purpose. As far as I can tell none of them need to be. \$\endgroup\$
    – Bill Barry
    Jul 9, 2012 at 22:36
  • \$\begingroup\$ Not knowing what the syntax was for GeoLocation in JS, I googled it, removed the parts I didn't need, and was left with this (after some other modifications). My question though is why would they be public in the first place, and how could the code improve, especially after removing them? \$\endgroup\$
    – Charlie
    Jul 9, 2012 at 23:03

1 Answer 1


None of this code needs to create any global variables. The pattern you have here is known as namespace creation.

It often follows the pattern:

var myNamespace = (function () {
    //private stuff
    var public = {}; //or function () ...
    //build up public object
    return public;

But sometimes the public object can be inlined like it can be in your case:

var geoLocateAddress = (function () {
    function init() {
    return { init: init };//unnecessary to expose the other functions as public

In this case, all you are doing with this namespaced global object is calling the init function. So instead of creating a global (generally considered bad taste in most languages) you can simply initialize the object:

(function () {
    function init() {

    init();//unnecessary to expose the other functions as public

(this pattern of having the function surrounding your code like this is commonly referred to as an IIFE)

Aside: for declaring a namespace I prefer the following form:

(function ($, window) {
    'use strict';

    window['geoLocateAddress'] = window['geoLocateAddress'] || {};
    window['geoLocateAddress'] = $.extend({}, window['geoLocateAddress'], {
        'init': init
}(jQuery, window));

Back on topic:

In my opinion, it is a bad practice to force the Javascript engine to go looking for your globals when you are not in global scope due to leaving off the window qualifier. Thus everywhere you reference console without calling it window.console (and the same goes for Navigator) or caching it in a local variable is wrong. In the event where you run this script outside of a browser that implements console you will get an exception. Navigator is slightly less of an issue because it is a reasonably safe assumption that you will not run this from a browser that doesn't supply a Navigator global namespace. For this reason I always pass the globals that I am going to use into my IIFE:

(function ($, geolocation, console) {
}(jQuery, Navigator.geolocation, window.console));

I would modify the rest of the code as follows; please comment if you want me to explain any of it in more detail and I'll try to get to it. Comments dictionary:

  • pref: personal preference (the opinions of others may vary)
  • rule: avoids possible issues with the code
  • possibility: potential source for further enhancement, outside of the scope of this question.
  • consideration: something I haven't decided one way or the other on yet

//pref: don't create global variables that are unnecessary
(function ($, geolocation, console) {//pref: pass in globals for munging purposes
    'use strict'; //pref: 100% on JsLint

    //pref: instead of defining one object variable and methods on it
    //we could define the methods and export an object at the end
    //this saves us from needing to do some sort of static object call syntax
    var updateAddressFields = function (data) { //pref: remove unused parameters
            console.log('Zip: ' + data.address.postalCode); 
            //pref: renaming variable provides very little benefit; 
            //outweighed by ability to simplify syntax by inlining to success 
            //function and then replacing the success function here
            console.dir(data); //pref: make above a constant string and use this instead of just logging zipcode
            $(function () {  //rule: don't update DOM until after the ready event
            //pref: further logging beyond start of function adds nothing but cruft to your log
        loadAddressByLocation = function (position) { //pref: renamed function for readability
            console.dir(position); //pref: inlined function to simplify code
            var data = { //possibility: abstract this as a jQuery helper if it has uses outside of setting zipcode (outside of this question scope)
                    lat : position.coords.latitude,
                    lng : position.coords.longitude
                url = "http://ws.geonames.org/findNearestAddressJSON"; //consideration: variable unnecessary?
            $.ajax({ //consideration: ajax vs getJSON?
                url: url,
                dataType: 'jsonp', //consideration: specify datatype or put callback in the url?
                data: data, //consideration: inline data definition?
                success: updateAddressFields, //pref: extra function wrapping unnecessary
                error: function (xhr, textStatus) {//perf: remove unused parameters
                    console.log(textStatus);//consideration: necessity of error function?
            //pref: return false did nothing here; removed

    console = console || { //rule: safe to remove shim if you know you're browser compat
        log: function () {}, //otherwise console may not exist under certain browsers
        dir: function () {}
    //perf: removed and inlined "return { init: init };" to not create globals
    console.log("Using your browser's GeoLocation API");//pref: inlined init and initEventHandlers for readability
    if (geolocation && geolocation.getCurrentPosition) { //rule: more behavior detection, also safe to remove if browser compat
        //assume correct api if this passes
}(jQuery, navigator.geolocation, window.console));
//pref: passing in navigator.geolocation will allow better minification (though I wouldn't minify this version anyway)
//rule: more behavior detection, referring to console as window.console to not trigger possible error referencing global that doesn't exist

Simplified for minification, I don't really see anything "wrong" with this version:

(function ($, geolocation) { //console removed
    if (geolocation) { //possibly unsafe if future browser implements geolocation but not getCurrentPosition, perhaps leave this as it was above
        geolocation.getCurrentPosition(function (position) {
            $.getJSON( //using this helper instead of ajax lets us not define an object and property names
                //dataType: 'jsonp', unnecessary with callback in url
                { //inlined data to remove var, IMO readability is not affected too much
                    lat : position.coords.latitude,
                    lng : position.coords.longitude
                function (data) { //unused params dropped from success callback
                    $(function () {
                        //don't update until after the ready event
}(jQuery, navigator.geolocation));

which shrinks down to 266 chars (via uglifyjs):

  • 1
    \$\begingroup\$ You're a javascript wizard. First question: So I always need to call window.console before console? \$\endgroup\$
    – Charlie
    Jul 10, 2012 at 1:19
  • \$\begingroup\$ Question two: Is this code flexible enough to reload the AJAX request, so that the page can we reloaded without actually reloading it? I feel like the code before your improvements would've been a pain to reload. \$\endgroup\$
    – Charlie
    Jul 10, 2012 at 1:26
  • 1
    \$\begingroup\$ 1: meh, you should reference a global variable in such a way that you don't have to be concerned when you run it in an environment where it doesn't exist. If you are going to use a variable more than once or twice, your code will probably benefit from caching the variable. The IIFE construct provides a simple cache scheme and gives a way to check existance by making it behave just like any other parameter. See also: jsfiddle.net/PCYQs \$\endgroup\$
    – Bill Barry
    Jul 10, 2012 at 2:17
  • \$\begingroup\$ 2: I'm not sure I understand your question; if you reload the page then it reloads all javascript and this would run again (and so make the ajax request again). \$\endgroup\$
    – Bill Barry
    Jul 10, 2012 at 2:21
  • \$\begingroup\$ 2: That's very true, however I might want to reload the geolocation function without reloading the rest of the page. Let's say other information on the page doesn't need to be reloaded, or is only there for the session (and I don't feel like dealing with cookies, or localstorage), then could I just reload the AJAX request and therefor get a new zipcode, if the location had changed? \$\endgroup\$
    – Charlie
    Jul 10, 2012 at 4:42

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