tiny standalone pubsub in javascript

pubsub.js

//PubSub
(function(attachTo, defaultContext) {
    var topics = {}, 
        attachTo = attachTo||this, 
        defaultContext = defaultContext||this,
        __slice = function (obj) { return [].prototype.slice.call(obj) };

    attachTo.publish = function() {
        var args = __slice(arguments),
            topic = args.shift();
        if (topics[topic]) {
            var currentTopic = topics[topic]||[];
            for (var i = 0, j = currentTopic.length; i < j; i++) {
                currentTopic[i].apply(null, args || []);
            }
        }
    };

    attachTo.subscribe = function(topic, callback, context) {
        var cb = callback.bind
            ? callback.bind(context||defaultContext)
            : function () {
                callback.apply(context||defaultContext, Array.prototype.slice.call(arguments));
            };
        if (!topics[topic]) topics[topic] = [];

        topics[topic].push(cb);

        return { "topic": topic, "callback": cb };
    };

    attachTo.unsubscribe = function(handle) {
        var topic = handle.topic;

        if (topics[topic]) {
            var currentTopic = topics[topic];

            for (var i = 0, j = currentTopic.length; i < j; i++) {
                if (currentTopic[i].callback === handle.callback) {
                    currentTopic.splice(i, 1);
                }
            }
        }
    };

})(my_container||window);