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);
})();