const ShoppingCart = function(name) {
  this.name = name;
  this.items = [];
  return this;
};

ShoppingCart.prototype.addItem = function(item) {
  this.items.unshift(item);
};

Object.defineProperty(ShoppingCart.prototype,
                      "count",
                      {get() { return this.items.length; }});

let cart = new ShoppingCart('james');
cart.addItem('socks');
cart.addItem('pants');
let cart2 = new ShoppingCart('semaj');
cart2.addItem('socks');
console.log(cart);
console.log(cart2);
// hm, I want to add some logging to addItem
ShoppingCart.prototype.addItem = function(item) {
  console.log(`adding item ${item} to ${this}`);
  this.items.push(item);
};
cart2.addItem('hat');
console.log(cart2.count, "items in cart2");

const OneSpoonCart = function(name, limit) {
  ShoppingCart.call(this, name);
  this.limit = limit;
  return this;
};
OneSpoonCart.prototype = Object.create(ShoppingCart.prototype);
OneSpoonCart.prototype.constructor = OneSpoonCart;

OneSpoonCart.prototype.addItem = function(item) {
  ShoppingCart.prototype.addItem.call(this, item);
  this.items = this.items.slice(0, this.limit);
};

let cart3 = new OneSpoonCart("james", 3);
console.log('limited cart', cart3);
cart3.addItem('socks');
cart3.addItem('hat');
cart3.addItem('pants');
cart3.addItem('gloves');
console.log('limited cart', cart3);
console.log(cart3.count, "items");