js中不引入第三变量交换两个变量值

一、算数运算

利用算数的特性将两个值互换，缺点：只适合数字类型，容易出现精度丢失

let x = 1, y = 2;
x = x + y; // x = 3
y = x - y; // y = 3 - 2
x = x - y; // x = 3 - 1
console.log(x, y); // 1 2

利用位运算实现交换，缺点：只适合整数

let x = -2, y = 1;
x ^= y; // x = 0011, y = 0010
y ^= x; // x = 0011, y = 0001
x ^= y; // x = 0010, y = 0001
console.log(x, y); // 1 2

利用JS弱类型特性，数组、对象都可以

let x = 2, y = 1;
x = [x, y]; // x = [2, 1]
y = x[0]; // y = 2
x = x[1]; // x = 1
console.log(x, y); // 1 2

let x = 2, y = 1;
x = { x, y }; // x = {x: 2, y: 1}
y = x.x; // y = 2
x = x.y; // x = 1
console.log(x, y); // 1 2

利用ES6解构，方便快捷

let x = 2, y = 1;
[x, y] = [y, x]; // x = 1 y =2
console.log(x, y); // 1 2

搞得花里胡哨的干啥

let x = 2, y = 1, temp;
temp = y; // temp = 1
y = x; // y = 2
x = temp; // x = 1
console.log(x, y); // 1 2