2. Crear una factura

let bill = {
    items: [
        { name: "Pizza", price: 5.99 },
        { name: "Wine", price: 7.99 },
        { name: "Meat", price: 4.99 },
        { name: "Bread", price: 1.99 },
        { name: "Water", price: 1.99 }
    ],
    getTax: function(){
        let sum = 0;
        for (let i = 0; i < this.items.length; i++) {
            sum += this.items[i].price;
        }
        return sum * 0.13;
    },
    getTotal: function(){
        let sum = 0;
        for (let i = 0; i < this.items.length; i++) {
            sum += this.items[i].price;
        }
        return sum + sum * 0.13;
    }
}

console.log(bill.getTax());
console.log(bill.getTotal());