Konami code IIFE, reproduces a Konami Code on both Firefox and Chrome

konami.bkmrk.js

(function () {
    // The Unicode keys
    var characterKeys = {
        u: 38,
        d: 40,
        l: 37,
        r: 39,
        a: 65,
        b: 66
    };
 
    // The Konami code
    var keys = ["u", "u", "d", "d", "l", "r", "l", "r", "b", "a"];
    var kbEvent = document.createEvent('KeyboardEvent');
 
    // Chromium Hack
    Object.defineProperty(kbEvent, 'keyCode', {
        get: function () {
            return this.keyCodeVal;
        }
    });
    Object.defineProperty(kbEvent, 'which', {
        get: function () {
            return this.keyCodeVal;
        }
    });
 
    // Creating the event
    var evtArgs = ["keydown", true, true, document.defaultView, false, false, false, false, 0, 0];
 
    // Here's the magic !
    for (var i = 0; i < keys.length; i += 1) {
        if (kbEvent.initKeyboardEvent) {
            evtArgs.splice(evtArgs.length - 2, 2, characterKeys[keys[i]], characterKeys[keys[i]]);
            kbEvent.initKeyboardEvent.apply(kbEvent, evtArgs);
        } else {
            evtArgs.splice(evtArgs.length - 2, 2, characterKeys[keys[i]], 0);
            kbEvent.initKeyEvent.apply(kbEvent, evtArgs);
        }
        kbEvent.keyCodeVal = characterKeys[keys[i]];
        document.body.dispatchEvent(kbEvent);
    }
})();

konami.bkmrk.min.js

(function(){var e={u:38,d:40,l:37,r:39,a:65,b:66},d="uuddlrlrba".split(""),a=document.createEvent("KeyboardEvent");Object.defineProperty(a,"keyCode",{get:function(){return this.keyCodeVal}});Object.defineProperty(a,"which",{get:function(){return this.keyCodeVal}});for(var c=["keydown",!0,!0,document.defaultView,!1,!1,!1,!1,0,0],b=0;b<d.length;b+=1)a.initKeyboardEvent?(c.splice(c.length-2,2,e[d[b]],e[d[b]]),a.initKeyboardEvent.apply(a,c)):(c.splice(c.length-2,2,e[d[b]],0),a.initKeyEvent.apply(a,c)),
a.keyCodeVal=e[d[b]],document.body.dispatchEvent(a)})();