解构赋值

解构赋值

数组的解构赋值

const arr = [1, 2, 3, 4];

let [a, b, c, d] = arr;

---

更复杂的匹配规则

const arr = ['a', 'b', ['c', 'd', ['e', 'f', 'g']]];

const [ , b] = arr;

const [ , , g] = ['e', 'f', 'g']

const [ , , [ , , g]] = ['c', 'd', ['e', 'f', 'g']];

const [ , , [ , , [ , , g]]] = arr;

---

扩展运算符 ...

const arr1 = [1, 2, 3];

const arr2 = ['a', 'b'];

const arr3 = ['zz', 1];

const arr4 = [...arr1, ...arr2, ...arr3];

const arr = [1, 2, 3, 4, 5, 6];

const [a, b, ...c] = arr;

---

// 默认值

const arr = [1, null, undefined];

const [a, b = 2, c, d = 'aaa'] = arr;

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// 交换变量

let a = 20;

let b = 10;

let temp;

temp = a;

a = b;

b = temp;

[a, b] = [b, a];

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接收多个 函数返回值

function getUserInfo(id) 
  *// .. ajax*
  return [
    true,
    {
      name: '小明',

      gender: '女',
      id: id
    },
    '请求成功'
  ];
};

const [status, data, msg] = getUserInfo(123);