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();
  };

  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) {
      $("#cartContainer").removeClass("hidden");
    }
  };
  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);
  };
  
  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;
  })

  return {
    // first chapter
    searchTerm: searchTerm,
    catalog: filteredCatalog,
    newProduct: newProduct,
    addProduct: addProduct,
    // second chapter
    cart: cart,
    showCartDetails: showCartDetails
  };
})();
ko.applyBindings(vm);