2023/12/231150字符
解构赋值
对象数据读取
const obj = {
name: 'bozai',
age: 18,
sex: 'boy',
address: {
city: '长治'
}
}
// 先定义变量,再从对象中拿取同名属性值
// 换名 添加默认值
const { name, age: year, sex, height = 180, address: { city }} = obj;
console.log(name, year, sex, height, city); //--> bozai 18 boy 180 长治
数组数据读取
const arr = [1, 2, 3, 4, {a: 'hello'}];
const [n1, , , n4] = arr; // n1, n4 --> 1 4
const {a} = arr[4]; // a --> "hello"
const [, num2, ...nums] = arr; // num2, nums --> 2 [3, 4, {a: "hello"}]
let a = 123;
{
let [a, b, c = 'null'] = [1, 2]; // 当变量被定义过后,容易出现变量已声明的情况。外部可以加一层括号来解决报错
console.log(a, b, c);
}
数据调换
let a = 1, b = 2;
[a, b] = [b, a]; // 数据调换
console.log(a, b); //--> 2 1
函数形参使用
function print ({name, age, sex} = obj) {
console.log(name, age, sex); //--> bozai 18 boy
}
print();