Event / Subscribable bus system with Ko Subscribables.

bus.js

 window.Bus = function(name, funcs, parent) {
	 	funcs = funcs instanceof Array === true ? funcs : [funcs];
	 	var bus = {};
	 	var sub = new ko.subscribable();
	 	var functionType = "function";
	 	bus.name = name;
	 	bus.children = [];
	 	bus.previousMessages = [];
	 	bus.extend = function(name, funcs) {
	 		var childBus = window.Bus(name, funcs, bus);
	 		bus.children.push(childBus);
	 		return childBus;
	 	};
	 	bus.subscribe = function(callbacks, target, parent) {
	 		var b = parent || bus;
	 		callbacks = callbacks instanceof Array === true ? callbacks : [callbacks];
	 		callbacks.forEach(function(callback) {
	 			sub.subscribe(callback, target, bus.name);
	 		});
	 		b.previousMessages.forEach(function(previousMessages) {
	 			callbacks.forEach(function(callback){
	 				callback(previousMessages);
	 			});
	 		});
	 		return bus;
	 	};
	 	bus.notify = function(value) {
	 		sub.notifySubscribers(value, bus.name);
	 		bus.previousMessages.push(value);
	 		bus.children.forEach(function(child) {
	 			child.notify(value);
	 		});
	 		return bus;

	 	};
	 	if (funcs !== undefined && funcs.filter(function(value) {
	 		return typeof value === functionType;
	 	}).length === funcs.length) {
	 		bus.subscribe(funcs, undefined, parent);
	 	}
	 	return bus;
	 };

	 var RouterBus = Bus("Router", function() {
	 	console.log("Router");
	 });
	 var MenuPage = RouterBus.extend("Router.Menu", function() {
	 	console.log("Menu");
	 });

	 MenuPage.notify(""); // One Menu log & one im a sub

	 var SubMenuPage = MenuPage.extend("Router.Menu.Sub", function() {
	 	console.log("im a sub"); //Should show once as there was a previous message in MenuPage
	 });

	 SubMenuPage.notify(""); //One im a sub
	 MenuPage.notify(""); // One Menu log & one im a sub
	 RouterBus.notify(""); // One Router Log and One Menu Log and im a sub