Miniature PubSub library in AMD pattern

pub-sub.js

define(function() {
    'use strict';

    var pubSub = function pubSubFn() {

        var topics = {};
        function subscribe(topic, listener) {
            // Create the topic's object if not yet created
            if (!topics[topic]) {
                topics[topic] = {
                    queue: []
                };
            }

            // Add the listener to queue
            var index = topics[topic].queue.push(listener) -1;

            // Provide handle back for removal of topic
            return {
                remove: function() {
                    delete topics[topic].queue[index];
                }
            };
        }

        function publish(topic, info) {
            // If the topic doesn't exist, or there's no listeners in queue, just leave
            if (!topics[topic] || !topics[topic].queue.length) {
                return;
            }

            // Cycle through topics queue, fire!
            var items = topics[topic].queue;
            items.forEach(function(item) {
                item(info || {});
            });
        }

        return {
            subscribe: subscribe,
            publish: publish
        };
    };

    return pubSub();
});