Js：交换两个变量的值

1、设置中间值：

let a = 1;
let b = 3;
let temp = null
temp = a;
a = b;
b = temp
console.log(a) // 3
console.log(b) // 1

2、解构赋值：

let a = 1;
let b = 3;
;[a,b] = [b,a]
console.log(a) // 3
console.log(b) // 1