safaribook-knockout-essentials/ko-cart/js/models/Product.js

"use strict";
var Product = function (id, name, price, stock) {
  "use strict";
  var _id = ko.observable(id),
    _name = ko.observable(name),
    _price = ko.observable(price),
    _stock = ko.observable(stock);
  var _lineColor = ko.computed(function() {
    return (_stock() < 5) ? 'red' : 'black';
  });
  return {
    id: _id,
    name: _name,
    price: _price,
    stock: _stock,
    lineColor: _lineColor
  };
};