解构赋值
let arr=[1,2,3,4]
let [a,b,c,d]=arr
console.log(a)
console.log(b)
console.log(c)
解构赋值： 交换变量
let a=1;
let b=2;
[a,b]=[b,a]
console.log(a)
console.log(b)