The for ... in loop iterates over the keys of the object, not the values. This results in name, price and discount being undefined. To fix this, we need to access the value of the key in the object.

const products = {
  SKU12345: { name: "Laptop", price: 999, discount: 0.1 },
  SKU67890: { name: "Phone", price: 499, discount: 0 },
  SKU54321: { name: "Tablet", price: 299, discount: 0.05 },
};

function printFormattedProductDetails(products) {
  for (const product in products) {
    const { name, price, discount } = products[product];

    let finalPrice = price;
    if (discount) {
      finalPrice = price - price * discount;
    }

    console.log(
      `Product: ${name}, Price: ${finalPrice.toLocaleString("en-US", {
        style: "currency",
        currency: "USD",
      })}`
    );
  }
}

printFormattedProductDetails(products);