ES6新增----解构赋值（数组解构）

2.数组解构：

参考学习：https://www.cnblogs.com/xiaohuochai/p/7243166.html

1.解构赋值
2.变量交换
3.嵌套数组解构
4.不定元素
5.数组复制

let colors = [ "red", "green", "blue" ];
let [ firstColor, secondColor ] = colors;
console.log(firstColor); // "red"
console.log(secondColor); // "green"

在解构模式中，也可以直接省略元素，只为感兴趣的元素提供变量名，thirdColor前的逗号是前方元素的占位符

let colors = [ "red", "green", "blue" ];
let [ , , thirdColor ] = colors;
console.log(thirdColor); // "blue"

1.解构赋值

let colors = [ "red", "green", "blue" ],
firstColor = "black",
secondColor = "purple";
[ firstColor, secondColor ] = colors;
console.log(firstColor); // "red"
console.log(secondColor); // "green"

2.变量交换

// 在 ES6 中互换值
let a = 1,
    b = 2;

[ a, b ] = [ b, a ];
console.log(a); // 2
console.log(b); // 1

3.嵌套数组解构

let colors = [ "red", [ "green", "lightgreen" ], "blue" ];
// 随后
let [ firstColor, [ secondColor ] ] = colors;
console.log(firstColor); // "red"
console.log(secondColor); // "green"

4.不定元素

let colors = [ "red", "green", "blue" ];
let [ firstColor, ...restColors ] = colors;
console.log(firstColor); // "red"
console.log(restColors.length); // 2
console.log(restColors[0]); // "green"
console.log(restColors[1]); // "blue"

5.数组复制

// 在 ES6 中克隆数组
let colors = [ "red", "green", "blue" ];
let [ ...clonedColors ] = colors;
console.log(clonedColors); //"[red,green,blue]"