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

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

  return {
    catalog: catalog,
    newProduct: newProduct,
    addProduct: addProduct,
  };
})();
ko.applyBindings(vm);