A subscribe/publish event manager class

EventSubPubManager.js

window.EventSubPubManager = window.EventSubPubManager || (function() {
    function EventSubPubManager() {
        this.__ = {}
    }

    EventSubPubManager.prototype.subscribe = function(topic, callback) {
        var callbacks = this.__[topic];

        if (!callbacks) {
            callbacks = this.__[topic] = [];
        }

        callbacks.push(callback);
    };

    EventSubPubManager.prototype.unsubscribe = function(topic, callback) {
        var callbacks = this.__[topic];

        if (callbacks) {
            callbacks.splice($(callbacks).index(callback), 1);

            if (callbacks.length === 0) {
                this.__[topic] = null;
                delete this.__[topic];
            }
        }
    };


    EventSubPubManager.prototype.publish = function(topic /*...args*/ ) {
        var callbacks = this.__[topic],
        targetCallbacks = [],
        args = Array.prototype.slice.call(arguments).splice(0, 1),
        i;

        if (callbacks) {
            for (i = 0; i < callbacks.length; i += 1) {
                targetCallbacks.push(callbacks[i]);
            }

            for (i = 0; i < targetCallbacks.length; i += 1) {
                targetCallbacks[i].apply(window, args);
            }
        }
    };

    return EventSubPubManager;
}());