Lightweight PubSub constructor

HowTo.js

var pubsub = new Pubsub();

pubsub.subscribe("someEvent", function (message) {
        console.log('Hello', messge);
});

pubsub.publish("someEvent", "world");

pubsub.unsubscribe("someEvent");

License

            DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
                    Version 2, December 2004

 Copyright (C) 2011 Mathieu ROBIN <http://www.mathieurobin.com>

 Everyone is permitted to copy and distribute verbatim or modified
 copies of this license document, and changing it is allowed as long
 as the name is changed.

            DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
   TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION

  0. You just DO WHAT THE FUCK YOU WANT TO.

PubSub.js

/**
 * Pub-Sub system, used for lightweight state machine
 *
 * @return {Object} Instance of Pubsub
 * @constructor
 */
function Pubsub () {
    "use strict";

    var subscription_registry = {},
        event = 0;

    return {
        /**
         * Publish method
         *
         * @param channel
         * @param message
         */
        publish     : function (channel, message) {
            var placeholder;

            for (placeholder in subscription_registry) {
                if (subscription_registry.hasOwnProperty(placeholder)) {
                    if (placeholder.split('-')[0] === channel) {
                        subscription_registry[placeholder](message);
                    }
                }
            }
        },
        /**
         * Subscription method
         *
         * @param channel
         * @param callback method
         */
        subscribe   : function (channel, callback) {
            subscription_registry[channel + --event] = callback;
        },
        /**
         * Unsubscription method
         *
         * @param channel
         */
        unsubscribe : function (channel) {
            var placeholder;

            for (placeholder in subscription_registry) {
                if (subscription_registry.hasOwnProperty(placeholder)) {
                    if (placeholder.split('-')[0] === channel) {
                        delete subscription_registry[placeholder];
                    }
                }
            }
        }
    };
}