Access Google Analytics Universal Analytics in external JS files

Question

In the old version of Google Analytics you could just add var _gaq = _gaq || []; on the top of your javascript files, which would let you push events and transactions before GA had fully loaded.

With Universal Analytics you no longer use .push(), so what is the proper way to create the ga object in external files where Google Analytics might not have loaded yet but you need to push events and transactions?

Answer 1

The Immediately-Invoked Function Expression in the Google Analytics snippet handles the creation of that object. In the snippet you see the following:

i[r] = i[r] || function() {
    (i[r].q = i[r].q || []).push(arguments)
}

We know from the parameters passed to the IIFE that i = window and r = "ga":

(function(i, s, o, g, r, a, m) {
    //...
})(window, document, 'script', '//www.google-analytics.com/analytics.js', 'ga');

In un-uglyfied JavaScript, the snippet reads as such:

window['ga'] = window['ga'] || function() {
    ( window['ga'].q =  window['ga'].q || []).push(arguments)
}

So by calling the global function ga, you are essentially creating an array that serves as the queue (if it doesn't already exist) and pushing values to the queue.

In Universal Analytics, calling this function:

ga('create', 'UA-XXXX-Y', 'auto');

Is the same as this in the previous version of GA:

var _gaq = _gaq || [];
_gaq.push(['_setAccount', 'UA-XXXX-Y']);

More info can be found in the Google dev docs.

Answer 2

You don't need to redefine the ga function since it already is defined in the tracking snippet. All you have to do is use the ga object in your external file and you are good to go. ga already is a global object, so no need to scope it.

You also don't want to be pushing anything into ga object before you at least run the line that creates the tracker:

ga('create', 'UA-XXXX-Y', 'auto');

If you d chances are the hit won't get through and won't reach your account.

Make sure that whatever external file you use you include it after the tracking snippet in your site, or maybe include the tracking snippet in the external file at the top.