A basic implementation of the Publish/Subscribe pattern by ExampleJS.com

PubSub.js

var PubSub = (function (window) {
    var uid, topics, ps;

    // Unique ID that gets incremented with every subscription.
    uid = 0;

    // Objects subscribe to a specific topic so this data structure
    // needs to be organized as a set of key-value pairs keyed to
    // those topics.
    topics = {};

    ps = {};

    ps.subscribe = function (topic, fn) {
        // If this topic does not yet exist, create it.
        if (!topics.hasOwnProperty(topic)) {
            topics[topic] = {};
        }

        // Register the function with the specified topic using a
        // unique ID as the key.
        topics[topic][++uid] = fn;

        // Return the unique ID for unsubscribing.
        return uid;
    };

    ps.unsubscribe = function (topic, id) {
        // Delete the function registered with the specified key in
        // the specified topic.
        if (topics[topic][id]) {
            delete topics[topic][id];
        }
    };

    ps.publish = function (topic, obj) {
        var key;

        // If this is a valid topic, then invoke every subscribed
        // function and pass the topic and specified object as the
        // arguments.
        if (topics.hasOwnProperty(topic)) {
            for (key in topics[topic]) {
                topics[topic][key](topic, obj);
            }
        }
    };

    ps.topics = function () {
        return topics;
    };

    window.PubSub = ps;
})(window);

PubSub2.js

var PubSub, Joe, Mom, Bank, Newspaper, IRS;

(function (ps) {
  var uid, topics;

	// 
	// Unique ID that gets incremented for every subscription.
	// 
	uid = 0;

	// 
	// Objects can subscribe to particular topics so the `topics` data structure needs to be
	// organized with key-value pairs keyed to those topics.
	// 
	topics = {};

	ps.subscribe = function (topic) {
		var i, l;

		// 
		// Add the specified topic to `topics` if `topics` does not already have a matching key.
		// 
		if (!topics.hasOwnProperty(topic)) {
			topics[topic] = {};
		}

		// 
		// Register any specified functions with this topic using a unique ID as the key.
		// 
		for (i = 1, l = arguments.length; i < l; i++) {
			topics[topic][++uid] = arguments[i];
		}

		// 
		// Return the unique ID used as the key for this subscription so we can later unsubscribe
		// from this topic if necessary.
		// 
		return uid;
	};

	ps.unsubscribe = function (topic, id) {
		// 
		// Delete the function stored in `topics` at the two keys defined by `topic` and `id`.
		// 
		if (topics[topic][id]) {
			delete topics[topic][id];
		}
	};

	ps.publish = function (topic, obj) {
		var key;

		// 
		// If `topic` is a valid property of the `topics` hash then iterate and invoke each function
		// paired with one of its keys.
		// 
		if (topics[topic]) {
			for (key in topics[topic]) {
				topics[topic][key](topic, obj);
			}
		}
	};

	ps.topics = function () {
		return topics;
	};
})(PubSub = {});

Joe = {
	occupation: function () {
		return 'plumber';
	},

	hometown: function () {
		return 'Stamford, Connecticut';
	},

	win: function () {
		var amount = 85000000;

		console.log('***** Joe wins the $' + amount + ' lottery jackpot!!! *****');

		PubSub.publish('jackpot', {
			amount: amount,
			hometown: this.hometown(),
			occupation: this.occupation()
		});
	}
};

Mom = {
	congrats: function (topic, data) {
		console.log('Mom says, "You know you were always my favorite child!"');
	}
};

Bank = {
	getBalance: function (topic, data) {
		console.log('Savings Account Balance: $' + (data.amount + 9.00));
	}
};

Newspaper = {
	headline: function (topic, data) {
		console.log('Tomorrow' + "'" + 's headline: "' + data.hometown + ' ' + data.occupation + ' wins $' + data.amount  + ' jackpot"');
	}
};

IRS = {
	tax: function (topic, data) {
		console.log('Dear Joe,\n\nYou owe $' + (data.amount * 0.5) + ' in taxes. Have a nice day.\n\nSincerely,\n\nThe I.R.S.');
	}
};

PubSub.subscribe('jackpot', Mom.congrats, Bank.getBalance, Newspaper.headline, IRS.tax);

Joe.win();