Javascript Homework Assignment

gistfile1.js

function PubSub() {
    this.events = {};
}
PubSub.prototype = {
    subscribe: function (e, callback, obj) { 
        if ( !this.events[e] ) this.events[e] = [];
        if ( typeof(e) != "string" || typeof(callback) != "function" ) return false;
        this.events[e].push({
            callback: callback,
            obj: obj
        });
        return true;
    },
    publish : function() {
        var e = arguments[0],
            args = 2 <= arguments.length ? Array().slice.call(arguments, 1) : [];
        if ( typeof(e) != "string" || !this.events[e] ) return false;
        var subscribers = this.events[e];
        for ( var i in subscribers ) (function(subscribers, i){
            setTimeout(function () {
                subscribers[i].callback.apply(subscribers[i].obj, args);
            }, 0);
        })(subscribers, i);
        return true;

    }
}