深入理解JavaScript系列（6）：S.O.L.I.D五大原则之单一职责SRP 转自 博客园 汤姆大叔

最终代码        function Event(name) {            var handlers = [];            this.getName = function () {                return name;            };            this.addHandler = function (handler) {                handlers.push(handler);            };            this.removeHandler = function (handler) {                for (var i = 0; i < handlers.length; i++) {                    if (handlers[i] == handler) {                        handlers.splice(i, 1);                        break;                    }                }            };            this.fire = function (eventArgs) {                handlers.forEach(function (h) {                    h(eventArgs);                });            };        }        function EventAggregator() {            var events = [];            function getEvent(eventName) {                return $.grep(events, function (event) {                    return event.getName() === eventName;                })[0];            }            this.publish = function (eventName, eventArgs) {                var event = getEvent(eventName);                if (!event) {                    event = new Event(eventName);                    events.push(event);                }                event.fire(eventArgs);            };            this.subscribe = function (eventName, handler) {                var event = getEvent(eventName);                if (!event) {                    event = new Event(eventName);                    events.push(event);                }                event.addHandler(handler);            };        }        function Product(id, description) {            this.getId = function () {                return id;            };            this.getDescription = function () {                return description;            };        }        function Cart(eventAggregator) {            var items = [];            this.addItem = function (item) {                items.push(item);                eventAggregator.publish("itemAdded", item);            };        }        function CartController(cart, eventAggregator) {            eventAggregator.subscribe("itemAdded", function (eventArgs) {                var newItem = $('<li></li>').html(eventArgs.getDescription()).attr('id-cart', eventArgs.getId()).appendTo("#cart");            });            eventAggregator.subscribe("productSelected", function (eventArgs) {                cart.addItem(eventArgs.product);            });        }        function ProductRepository() {            var products = [new Product(1, "Star Wars Lego Ship"),            new Product(2, "Barbie Doll"),            new Product(3, "Remote Control Airplane")];            this.getProducts = function () {                return products;            }        }        function ProductController(eventAggregator, productRepository) {            var products = productRepository.getProducts();            function onProductSelected() {                var productId = $(this).attr('id');                var product = $.grep(products, function (x) {                    return x.getId() == productId;                })[0];                eventAggregator.publish("productSelected", {                    product: product                });            }            products.forEach(function (product) {                var newItem = $('<li></li>').html(product.getDescription())                                    .attr('id', product.getId())                                    .dblclick(onProductSelected)                                    .appendTo("#products");            });        }        (function () {            var eventAggregator = new EventAggregator(),                cart = new Cart(eventAggregator),                cartController = new CartController(cart, eventAggregator),                productRepository = new ProductRepository(),                productController = new ProductController(eventAggregator, productRepository);        })();