safaribook-knockout-essentials/ko-cart/js/viewmodel.js

var vm = (function () {
    "use strict";

    var visibleCatalog = ko.observable(true);
    var visibleCart = ko.observable(false);

    var catalog = ko.observableArray([
        Product(1, "T-Shirt", 10.0, 20),
        Product(2, "Trousers", 20.0, 10),
        Product(3, "Shirt", 15.0, 20),
        Product(4, "Shorts", 5.0, 10),
    ]);

    var newProduct = Product("", "", "", "");
    var clearNewProduct = function () {
        newProduct.name("");
        newProduct.price("");
        newProduct.stock("");
    };

    var addProduct = function (context) {
        var id = new Date().valueOf(); // random id from time

        var product = Product(
            id,
            context.name(),
            context.price(),
            context.stock()
        );
        catalog.push(product);
        clearNewProduct();
        $('#addToCatalogModal').modal('hide');

    };

    var searchTerm = ko.observable("");
    var filteredCatalog = ko.computed(function () {
        // if catalog is empty return empty array
        if (!catalog()) {
            return [];
        }
        var filter = searchTerm().toLowerCase();
        // if filter is empty return all the catalog
        if (!filter) {
            return catalog();
        }
        //filter data
        var filtered = ko.utils.arrayFilter(catalog(), function (item) {
            var strProp = ko.unwrap(item["name"]).toLocaleLowerCase();
            return strProp.indexOf(filter) > -1;
        });
        return filtered;
    });

    var cart = ko.observableArray([]);
    var showCartDetails = function () {
        if (cart().length > 0) {
            visibleCart(true);
        }
    };
    var addToCart = function (data) {
        var item = null;
        var tmpCart = cart();
        var n = tmpCart.length;
        while (n--) {
            if (tmpCart[n].product.id() === data.id()) {
                item = tmpCart[n];
            }
        }
        if (item) {
            item.addUnit();
        } else {
            item = new CartProduct(data, 0);
            item.addUnit();
            tmpCart.push(item);
        }
        cart(tmpCart);
    };

    // The cart-widget template
    var totalItems = ko.computed(function () {
        var tmpCart = cart();
        var total = 0;
        tmpCart.forEach(function (item) {
            total += parseInt(item.units(), 10);
        });
        return total;
    });
    var grandTotal = ko.computed(function () {
        var tmpCart = cart();
        var total = 0;
        tmpCart.forEach(function (item) {
            total += item.units() * item.product.price();
        });
        return total;
    });

    // The cart-item template
    var removeFromCart = function (data) {
        var units = data.units();
        var stock = data.product.stock();
        data.product.stock(units + stock);
        cart.remove(data);
    };

    // The cart template
    var hideCartDetails = function () {
        visibleCart(false);
    };
    var showOrder = function () {
        visibleCatalog(false);
    };

    // The order template
    var showCatalog = function () {
        visibleCatalog(true);
    };
    var finishOrder = function () {
        cart([]);
        hideCartDetails();
        showCatalog();
        $("#finishOrderModal").modal("show");
    };


    return {
        // first chapter
        searchTerm: searchTerm,
        catalog: filteredCatalog,
        newProduct: newProduct,
        addProduct: addProduct,
        // second chapter
        cart: cart,
        showCartDetails: showCartDetails,
        addToCart: addToCart,
        totalItems: totalItems,
        grandTotal: grandTotal,
        removeFromCart: removeFromCart,
        hideCartDetails: hideCartDetails,
        showOrder: showOrder,
        showCatalog: showCatalog,
        finishOrder: finishOrder,
        visibleCatalog: visibleCatalog,
        visibleCart: visibleCart,
    };
})();

var templates = [
    "header",
    "catalog",
    "cart",
    "cart-item",
    "cart-widget",
    "order",
    "add-to-catalog-modal",
    "finish-order-modal",
];

var busy = templates.length;
templates.forEach(function (tpl) {
    "use strict";
    $.get("views/" + tpl + ".html").then(function (data) {
        $("body").append(data);
        busy--;
        if (!busy) {
            ko.applyBindings(vm);
        }
    });
});