js如何实现购物车功能

const cart = [];

function addToCart(item) {
  cart.push(item);
}

function getCartCount() {
  return cart.length;
}

function removeFromCart(index) {
  cart.splice(index, 1);
}

function getAllItems() {
  return cart;
}

function clearCart() {
  cart.length = 0;
}

function calculateTotalPrice() {
  let total = 0;
  for (let item of cart) {
    total += item.price * item.quantity;
  }
  return total;
}

const addToCartBtn = document.getElementById("add-to-cart-btn");
addToCartBtn.addEventListener("click", () => {
  const item = {
    name: "Product Name",
    price: 100,
    quantity: 1
  };
  addToCart(item);
  updateCartUI();
});

function updateCartUI() {
  const cartCountElement = document.getElementById("cart-count");
  cartCountElement.textContent = getCartCount();
  const totalPriceElement = document.getElementById("total-price");
  totalPriceElement.textContent = calculateTotalPrice();
}