JavaScript中剩余参数的使用详解

const arr = [1, 2, ...[3, 4]];
console.log(arr);

// REST, because on LEFT side of =
const [a, b, ...others] = [1, 2, 3, 4, 5];
// ...others 收集数组中未使用的元素
console.log(a, b, others);

const restaurant = {
    name: '意大利🇮🇹经典',
    location: 'Via Angelo Tavanti 23, 佛罗伦萨, 意大利',
    categories: ['意大利', '比萨店', '素食', '有机'],
    starterMenu: ['佛卡夏', '意式烤面包', '大蒜面包', '卡普雷塞沙'],
    mainMenu: ['披萨', '意大利面', '烩饭'],
};
const [pizza, , risotto, ...otherFood] = [
    ...restaurant.mainMenu,
    ...restaurant.starterMenu
];
console.log(pizza, risotto, otherFood);

const [pizza, , risotto, ...otherFood, bread] = [
    ...restaurant.mainMenu,
    ...restaurant.starterMenu
];	// An Error will be occur!将会出现一个错误
console.log(pizza, risotto, otherFood);

const restaurant = {
    name: '意大利🇮🇹经典',
    location: 'Via Angelo Tavanti 23, 佛罗伦萨, 意大利',
    categories: ['意大利', '比萨店', '素食', '有机'],
    starterMenu: ['佛卡夏', '意式烤面包', '大蒜面包', '卡普雷塞沙'],
    mainMenu: ['披萨', '意大利面', '烩饭'],
    openingHours: {
        thu: {
            open: 12,
            close: 22,
        },
        fri: {
            open: 11,
            close: 23,
        },
        sat: {
            open: 0, // Open 24 hours
            close: 24,
        },
    },
};

const { sat, ...weekdays } = restaurant.openingHours;
console.log(sat, weekdays);

const add = function (num1, num2) {
    console.log(numb1, num2);
}
add(2, 3);

const add = function (...numbers) {
    console.log(numbers);
}
add(2, 3);
add(5, 3, 7, 2);
add(8, 2, 5, 3, 2, 1, 4);

const add = function (...numbers) {
    let sum = 0;
    for (let i = 0; i < numbers.length; i++) {
        sum += numbers[i];
    }
    return sum;
}
console.log(add(2, 3));  // 5
console.log(add(5, 3, 7, 2));    // 17
console.log(add(8, 2, 5, 3, 2, 1, 4));   // 25

const x = [23, 5, 7];
console.log(add(...x));  // 利用展开语法再次将数组打包📦

const restaurant = {
    name: '意大利🇮🇹经典',
    location: 'Via Angelo Tavanti 23, 佛罗伦萨, 意大利',
    categories: ['意大利', '比萨店', '素食', '有机'],
    starterMenu: ['佛卡夏', '意式烤面包', '大蒜面包', '卡普雷塞沙'],
    mainMenu: ['披萨', '意大利面', '烩饭'],
    orderPizza: function (mainIngredient, ...otherIngredients) {
        console.log(mainIngredient);
        console.log(otherIngredients);
    }
};
restaurant.orderPizza('蘑菇🍄', '葱', '橄榄🫒', '菠菜🥬');

restaurant.orderPizza('蘑菇🍄', '葱', '橄榄🫒', '菠菜🥬');	//蘑菇🍄,
							    // ['葱', '橄榄🫒', '菠菜🥬']
restaurant.orderPizza('蘑菇🍄');	// 蘑菇🍄 
				        // []