curriculum/challenges/english/blocks/learn-basic-oop-by-building-a-shopping-cart/63efdbc22a0c56070beabed7.md
You’re on the right track! However, let’s take a moment to address a common issue when working with objects in JavaScript.
When you try to access an object property that doesn’t exist, JavaScript returns undefined. If you then attempt to perform arithmetic operations on undefined, it can lead to unexpected results, such as NaN.
To prevent this, you can use the || (logical OR) operator to provide a default value.
let scores = {};
let players = ["Alice", "Bob", "Charlie"];
players.forEach(player => {
scores[player] = scores[player] || 0;
});
Now, let’s apply this concept to your totalCountPerProduct object in the forEach callback. Make sure that each dessert.id property is initialized properly.
Initialize totalCountPerProduct[dessert.id] with a default value of 0 using the || operator.
You should use dot notation to access the id property of dessert.
const cart = new ShoppingCart();
assert.match(cart.addItem.toString(), /dessert\.id/);
You should use bracket notation to access the property of totalCountPerProduct that corresponds to dessert.id.
const cart = new ShoppingCart();
assert.match(cart.addItem.toString(), /totalCountPerProduct\s*\[\s*dessert\.id\s*\]/);
You should initialize totalCountPerProduct[dessert.id] with 0 as a default value using || operator at the end of the expression.
const cart = new ShoppingCart();
assert.match(cart.addItem.toString(), /totalCountPerProduct\s*\[\s*dessert\.id\s*\]\s*=\s*totalCountPerProduct\s*\[\s*dessert\.id\s*\]\s*\|\|\s*0\s*/);
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>freeCodeCamp Shopping Cart</title>
<link rel="stylesheet" href="./styles.css" />
</head>
<body>
<header>
<h1 class="title">Desserts Page</h1>
</header>
<main>
<button id="cart-btn" type="button" class="btn">
<span id="show-hide-cart">Show</span> Cart
</button>
<div id="cart-container">
<button class="btn" id="clear-cart-btn">Clear Cart</button>
<div id="products-container"></div>
<p>Total number of items: <span id="total-items">0</span></p>
<p>Subtotal: <span id="subtotal">$0</span></p>
<p>Taxes: <span id="taxes">$0</span></p>
<p>Total: <span id="total">$0</span></p>
</div>
<div id="dessert-card-container"></div>
</main>
<script src="./script.js"></script>
</body>
</html>
*,
*::before,
*::after {
margin: 0;
padding: 0;
box-sizing: border-box;
}
:root {
--dark-grey: #1b1b32;
--light-grey: #f5f6f7;
--black: #000;
--white: #fff;
--grey: #3b3b4f;
--golden-yellow: #fecc4c;
--yellow: #ffcc4c;
--gold: #feac32;
--orange: #ffac33;
--dark-orange: #f89808;
}
body {
background-color: var(--dark-grey);
}
.title {
color: var(--light-grey);
text-align: center;
margin: 25px 0;
}
#dessert-card-container {
display: flex;
flex-direction: column;
flex-wrap: wrap;
align-items: center;
}
.dessert-card {
background-color: var(--light-grey);
padding: 15px;
text-align: center;
border-radius: 15px;
margin: 20px 10px;
}
.dessert-price {
font-size: 1.2rem;
}
.btn {
display: block;
cursor: pointer;
width: 100px;
color: var(--dark-grey);
background-color: var(--gold);
background-image: linear-gradient(var(--golden-yellow), var(--orange));
border-color: var(--gold);
border-width: 3px;
}
.btn:hover {
background-image: linear-gradient(var(--yellow), var(--dark-orange));
}
#cart-btn {
position: absolute;
top: 0;
right: 0;
}
.add-to-cart-btn {
margin: 30px auto 10px;
}
#cart-container {
display: none;
position: absolute;
top: 60px;
right: 0;
background-color: var(--light-grey);
width: 200px;
height: 400px;
border: 8px double var(--black);
border-radius: 15px;
text-align: center;
font-size: 1.2rem;
overflow-y: scroll;
}
.product {
margin: 25px 0;
}
.product-count {
display: inline-block;
margin-right: 10px;
}
.product-category {
margin: 10px 0;
}
@media (min-width: 768px) {
#dessert-card-container {
flex-direction: row;
}
.dessert-card {
flex: 1 0 21%;
}
#cart-container {
width: 300px;
}
}
const cartContainer = document.getElementById("cart-container");
const productsContainer = document.getElementById("products-container");
const dessertCards = document.getElementById("dessert-card-container");
const cartBtn = document.getElementById("cart-btn");
const clearCartBtn = document.getElementById("clear-cart-btn");
const totalNumberOfItems = document.getElementById("total-items");
const cartSubTotal = document.getElementById("subtotal");
const cartTaxes = document.getElementById("taxes");
const cartTotal = document.getElementById("total");
const showHideCartSpan = document.getElementById("show-hide-cart");
let isCartShowing = false;
const products = [
{
id: 1,
name: "Vanilla Cupcakes (6 Pack)",
price: 12.99,
category: "Cupcake",
},
{
id: 2,
name: "French Macaron",
price: 3.99,
category: "Macaron",
},
{
id: 3,
name: "Pumpkin Cupcake",
price: 3.99,
category: "Cupcake",
},
{
id: 4,
name: "Chocolate Cupcake",
price: 5.99,
category: "Cupcake",
},
{
id: 5,
name: "Chocolate Pretzels (4 Pack)",
price: 10.99,
category: "Pretzel",
},
{
id: 6,
name: "Strawberry Ice Cream",
price: 2.99,
category: "Ice Cream",
},
{
id: 7,
name: "Chocolate Macarons (4 Pack)",
price: 9.99,
category: "Macaron",
},
{
id: 8,
name: "Strawberry Pretzel",
price: 4.99,
category: "Pretzel",
},
{
id: 9,
name: "Butter Pecan Ice Cream",
price: 2.99,
category: "Ice Cream",
},
{
id: 10,
name: "Rocky Road Ice Cream",
price: 2.99,
category: "Ice Cream",
},
{
id: 11,
name: "Vanilla Macarons (5 Pack)",
price: 11.99,
category: "Macaron",
},
{
id: 12,
name: "Lemon Cupcakes (4 Pack)",
price: 12.99,
category: "Cupcake",
},
];
products.forEach(
({ name, id, price, category }) => {
dessertCards.innerHTML += `
<div class="dessert-card">
<h2>${name}</h2>
<p class="dessert-price">$${price}</p>
<p class="product-category">Category: ${category}</p>
<button
id="${id}"
class="btn add-to-cart-btn">Add to cart
</button>
</div>
`;
}
);
class ShoppingCart {
constructor() {
this.items = [];
this.total = 0;
this.taxRate = 8.25;
}
--fcc-editable-region--
addItem(id, products) {
const product = products.find((item) => item.id === id);
const { name, price } = product;
this.items.push(product);
const totalCountPerProduct = {};
this.items.forEach((dessert) => {
})
}
--fcc-editable-region--
};