Function Call Stack GA Style

hello.js

var Hello = function(argv){

    if(argv instanceof Array){
        while(f = argv.shift()) {
            this.push(f);
        }
    }

    return this;
}

Hello.prototype = {
    color: 'black',
    _setColor: function(color){
        this.color = color;
    },
    _sayHello: function(el){
        var e = document.getElementById(el) || this.crateEl();
        e.innerText = "HELLO!";
        e.style.color = this.color;
    },
    push: function(arr){
        if(!arr) return false;
        
        // Some triggers
        f_name = arr.shift();
        console.log("Invoke function: " + f_name, arr)
        
        this[f_name].apply(this, arr); // Need some validation.
        return true;
    },
    createEl: function(){
        var el = document.createElement('div');
        document.body.insertBefore(el);
        return el;
    }
}

document.body.addEventListener('load', function(){
    console.log("Before load", _q);

    var _q = new Hello(_q);
    
    console.log("After load", _q);
})

index.html

<script>
    var _q = _q || [];
    _q.push(["_setColor", "red"]);
    _q.push(["_sayHello"])
</script>
<script src="hello.js"></script>