neverforget.js

(function(){

    // normal ass object:
    var obj = {
        me:37
    };
    
    function mangler(arg, num){
        // `arg` is literally `obj`
        arg.me = num;
        
        // `other`, by reference, is also `obj`
        var other = arg;
        other.me = num * 2;
    }
    
    console.log(obj.me); // 37
    mangler(obj, 10);
    console.log(obj.me); // 20

})();