javascript - OPTIONAL CHAINING 和 NULLISH COALESCING 运算符的组合未呈现预期结果

Question

我只是在学习可选链和空值合并的组合。这里是object

const restaurant = {
name_: 'Classico Italiano',
location: 'Via Angelo Tavanti 23, Firenze, Italy',
categories: ['Italian', 'Pizzeria', 'Vegetarian', 'Organic'],
starterMenu: ['Focaccia', 'Bruschetta', 'Garlic Bread', 'Caprese Salad'],
mainMenu: ['Pizza', 'Pasta', 'Risotto'],

openingHours: {
    thu: {
        open: 12,
        close: 22,
    },
    fri: {
        open: 11,
        close: 23,
    },
    sat: {
        open: 0, // Open 24 hours
        close: 24,
    },
},
orderPizza(ing1, ing2) {
    console.log(`you have ordered your pizza with ${ing1} and ${ing2}`);
}};

当我试图检查该方法是否存在时，无论如何它都会打印出它们。我做错了什么？

console.log(restaurant.orderPizza?.('some', 'something') ?? 'no method exist');

Answer 1

也许从函数返回一个值，否则它有一个未定义的值：

const restaurant1 = {
  name_: 'Classico Italiano',
  orderPizza(ing1, ing2) {
    return `you have ordered your pizza with ${ing1} and ${ing2}`;
  }
};

const restaurant2 = {
  name_: 'Other',
};

console.log(restaurant1.orderPizza?.('some', 'something') ?? 'no method exist');
console.log(restaurant2.orderPizza?.('some', 'something') ?? 'no method exist');