ES6解构赋值语法详解：数组、对象及函数参数应用

const numbers = [1, 2, 3, 4, 5];

const [a, b, c, d, e] = numbers;

console.log(a); // 输出 1
console.log(b); // 输出 2
console.log(c); // 输出 3
console.log(d); // 输出 4
console.log(e); // 输出 5

const numbers = [1, 2];

const [a, b, c = 3] = numbers;

console.log(a); // 输出 1
console.log(b); // 输出 2
console.log(c); // 输出 3

const nestedArray = [1, [2, [3, 4]]];
const [a, [b, [c, d]]] = nestedArray;

console.log(a); // 输出 1
console.log(b); // 输出 2
console.log(c); // 输出 3
console.log(d); // 输出 4

const person = {
  name: 'Alice',
  age: 30,
  city: 'New York'
};

const { name, age, city } = person;

console.log(name); // 输出 'Alice'
console.log(age); // 输出 30
console.log(city); // 输出 'New York'

const person = {
  name: 'Alice',
  age: 30
};

const { name, age, city = 'New York' } = person;

console.log(name); // 输出 'Alice'
console.log(age); // 输出 30
console.log(city); // 输出 'New York'

const nestedObject = {
  prop1: 'value1',
  prop2: {
    nestedProp1: 'value2',
    nestedProp2: {
      deeplyNestedProp: 'value3'
    }
  }
};

const { prop1, prop2: { nestedProp1, nestedProp2: { deeplyNestedProp } } } = nestedObject;

console.log(prop1); // 输出 'value1'
console.log(nestedProp1); // 输出 'value2'
console.log(deeplyNestedProp); // 输出 'value3'

function printUserInfo({ name, age, city }) {
  console.log(`Name: ${name}`);
  console.log(`Age: ${age}`);
  console.log(`City: ${city}`);
}

const user = {
  name: 'Alice',
  age: 30,
  city: 'New York'
};

printUserInfo(user);

function sum([a, b, c]) {
  console.log(a + b + c);
}

const numbers = [1, 2, 3];

sum(numbers);

let [a, b, c] = 'ES6';
console.log(a, b, c)	// E S 6

let {length : l} = 'ES6';
console.log(l) // 3

let {a1: b1} = 666;
console.log(b1);	// undefined
let {a2: b2} = true;
console.log(b2);	// undefined
let {a3: b3} = undefined;
console.log(b3);	// 报错
let {a4: b4} = null;
console.log(b4);	// 报错