Make variable a function in javascript

Question

I'm currently trying to do something like Google Analytics and make a data-transfer/tracking script using Javascript.

My approach is, that I want to make a short script/snippet to implement on a site like Google Analytics' tracking script - this part is quite easy.

The problem is, that with Google analytics, they're creating a ga-variable in the snippet (the code on the website), and the setting variables like this:

ga('create', 'TRACK-ID');
ga('send', 'something', 'something);

The JavaScript-snippet that is inserted in the HTML-pages is (just like Google Analytics'):

(function(i, s, o, g, r, a, m){
    i['ChurnimizerTrackObj'] = r;

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

    i[r].l = 1 * new Date();

    o = o || "script";

    a       = s.createElement(o),
    m       = s.getElementsByTagName(o)[0];

    a.async = 1;
    a.src   = g;

    m.parentNode.insertBefore(a, m)
})(window, document, 'script', 'cm.js', 'ga');

ga('send', 'test');     
ga('create', 'TR-XXXXXX');

Well, I can make the ga-variable and insert an alert event in my "local"-file (the JS-file, that should do all the logic), but I can't get to why my function isn't working as the above? My local file is:

(
function(){
    alert("something");

    (
        return (function(a, b, c){
            alert("test");

            switch(a){
                case "create":
                    alert("A is create");
                case "send":
                    alert("A is send");
            }
            alert(a);
        })()
    );
}
)();

The problem is, that when I use the function "ga", it won't alert either the create-alert or the send-alert.

EDIT 1:

WHAT I want to know is, how I can get the function parameters from the "ga" variable in the local file?

My alerts with the static messages is fired correctly - but my approach to returning a function and alerting it's parameters just leaves the parameter-values as "undefined", where I wan't them to be "send", "create" and so on.

EDIT 2:

What I want is to pass variables from the Snippet to the local javascript-file by just writing the variable name ga as a function name. Like:

ga('send', 'someStr', 'someVal');

How do I get to the state, where I can use my ga-variable as a function setting some information in the local file? :-)

ga('send', 'something', 'something); typo? BTW, I can't understand what you trying to achieve. — DontVoteMeDown
– DontVoteMeDown, Commented Feb 5, 2014 at 18:39
Ok, i almost see what you are asking. However, it seems like you are lacking an understanding of what your local analytics code is doing. in the google code, they are passing their function into the global window scope, and then assigning its arguments array to the property q of the ga object. — MaxPRafferty
– MaxPRafferty, Commented Feb 5, 2014 at 18:59

Jess · Accepted Answer · 2014-04-04 13:27:29Z

5

This works better. You need break statements inside your switch.

EDIT: I also changed the code so you can attach the new function to anything you want, in this example, the window. You can also pass in a name for the function, in this example, ga.

(function(obj,name){
    alert("something");

    obj[name] = function(a, b, c){
        alert("test");

        switch(a){
            case "create":
                alert("A is create"); break;
            case "send":
                alert("A is send"); break;
        }
        alert(a);
    };
})(window,'ga');

Now you can call ga like this:

ga('create','a','b');

edited Apr 4, 2014 at 13:27

answered Feb 5, 2014 at 18:40

Jess

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5 Comments

DontVoteMeDown Over a year ago

Now I see something logic on this post. +1

denlau Over a year ago

Hey Jess, Well, I thought that too, BUT in the Javascript snippet I want the user to have the possibility to name the variable whatever he wants. That's what's happening in 5th parameter "r"..

denlau Over a year ago

The problem is now, that even though I actually try both ga('create','someKey','someVal') and ga('send','someKey','someVal'); i don't get any alerts as suppossed?

Jess Over a year ago

I run the 2 snips of code from my answer in the Chrome Console. I get all the alerts... What are you doing?

MaxPRafferty Over a year ago

@denlau this code seems to accomplish what you want - it will give you access in your external JS file to the three variables a, b, and c that are passed in. It is your job to do something with them once they are there.

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