pubsub-simple.js

define([], function() {
    /* See also: "Learning Javascript Design Patterns" by Addy Osmani
    * http://addyosmani.com/resources/essentialjsdesignpatterns/book/
    *
    * for examples on how to use pubsub as event aggregator (Mediator)
    *
    */ 
    var pubsub = function(){};
    (function(q) {
        var topics = {}, subUid = -1;
        q.subscribe = function(topic, func) {
            if (!topics[topic]) {
                topics[topic] = [];
            }
            var token = (++subUid).toString();
            topics[topic].push({
                token: token,
                func: func
            });
            return token;
        };

        q.publish = function(topic, args) {
            if (!topics[topic]) {
                return false;
            }
            setTimeout(function() {
                var subscribers = topics[topic],
                    len = subscribers ? subscribers.length : 0;

                while (len--) {
                    subscribers[len].func(topic, args);
                }
            }, 0);
            return true;

        };

        q.unsubscribe = function(token) {
            for (var m in topics) {
                if (topics[m]) {
                    for (var i = 0, j = topics[m].length; i < j; i++) {
                        if (topics[m][i].token === token) {
                            topics[m].splice(i, 1);
                            return token;
                        }
                    }
                }
            }
            return false;
        };
    }(pubsub));
    return pubsub;
});