Single Responsibility Principle Example - Version 2

by shengoo

HTML

<div class="products-wrapper">
    <h2>Products</h2>
    <ul id="products"></ul>
</div>

<div class="cart-wrapper">
    <h2>Cart</h2>
    <ul id="cart"></ul>
</div>

CSS

ul {
            border: 1px solid black;
            width: 200px;
            min-height: 100px;
        }

        .cart-wrapper {
            float: left;
            margin-left: 20px;
        }

        .products-wrapper {
            float: left;
        }

JavaScript

function Event(name) {
    this._handlers = [];
    this.name = name;
}
Event.prototype.addHandler = function(handler) {
    this._handlers.push(handler);
};
Event.prototype.removeHandler = function(handler) {
    for (var i = 0; i < handlers.length; i++) {
        if (this._handlers[i] == handler) {
            this._handlers.splice(i, 1);
            break;
        }
    }
};
Event.prototype.fire = function(eventArgs) {
    this._handlers.forEach(function(h) {
        h(eventArgs);
    });
};

var eventAggregator = (function() {
    var events = [];

    function getEvent(eventName) {
        return $.grep(events, function(event) {
            return event.name === eventName;
        })[0];
    }

    return {
        publish: function(eventName, eventArgs) {
            var event = getEvent(eventName);

            if (!event) {
                event = new Event(eventName);
                events.push(event);
            }
            event.fire(eventArgs);
        },

        subscribe: function(eventName, handler) {
            var event = getEvent(eventName);

            if (!event) {
                event = new Event(eventName);
                events.push(event);
            }

            event.addHandler(handler);
        }
    };
})();

function Cart() {
    var items = [];

    this.addItem = function(item) {
        items.push(item);
        eventAggregator.publish("itemAdded", item);
    };
}

var cartView = (function() {
    eventAggregator.subscribe("itemAdded", function(eventArgs) {
        var newItem = $('<li></li>')
            .html(eventArgs.getDescription())
            .attr('id-cart', eventArgs.getId())
            .appendTo("#cart");
    });
})();

var cartController = (function(cart) {
    eventAggregator.subscribe("productSelected", function(eventArgs) {
        cart.addItem(eventArgs.product);
    });
})(new Cart());

function Product(id, description) {
    this.getId = function() {
        return id;
    };
    this.getDescription =...