十.数组解构

Posted 2020-11-22 wangrong-smile

const numbers = [‘one‘, ‘two‘, ‘three‘, ‘four‘]

　　

es5:

const one = numbers[0];    //one     
const two = numbers[1];    //two

　　

es6: 获取到相应位置的数组原素的值

const [one, two] = numbers;

console.log(one,two);　　//one two

//如果要获取数组0跟3 位置的元素的话,把那个位置留出来就行
const [one, , tow] = numbers;

//如果你想获取第一个元素的值和后面所有元素的值的话 (...others必须是在最后的一个位置)
const [one,...others] = numbers;
console.log(one,others);　　// one ["two","three","four"]

　　

es6默认参数：

const details = [‘JellyBool‘, ‘wangrong.com‘, null];

const [name,website,category= ‘php‘] = details;

console.log(name, website, category);    // JellyBool wangrong.com null (只有category为undefined时，category值才为Php)

　　

例子：交换 a 跟 b 的值

let a = 10;
let b = 20;

 

es5:

let temp;
temp = a;
a = b;
b = temp;
console.log(a,b);    //20 10

　　

es6:

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

console.log(a,b);    //20 10