javascript observerパターン

javascript observerパターン
http://www.addyosmani.com/resources/essentialjsdesignpatterns/book/#observerpatternjavascript
Observer implementation

var pubsub = {};
(function(q) {

    var topics = {},
        subUid = -1;

    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.subscribe = function(topic, func) {

        if (!topics[topic]) {
            topics[topic] = [];
        }

        var token = (++subUid).toString();
        topics[topic].push({
            token: token,
            func: func
        });
        return token;
    };

    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));

Subscribing and publishing

var testSubscriber = function( topics , data ){
    console.log( topics + ": " + data );
};


// Publishers are in charge of "publishing" notifications about events

pubsub.publish( 'example1', 'hello world!' );
pubsub.publish( 'example1', ['test','a','b','c'] );
pubsub.publish( 'example1', [{'color':'blue'},{'text':'hello'}] );



//  Subscribers basically "subscribe" (or listen)
// And once they've been "notified" their callback functions are invoked
var testSubscription = pubsub.subscribe( 'example1', testSubscriber );


// Unsubscribe if you no longer wish to be notified

setTimeout(function(){
    pubsub.unsubscribe( testSubscription );
}, 0);

pubsub.publish( 'example1', 'hello again! (this will fail)' );