JavaScript中A与B互换的三种方法

第一种：常规置换，借助中间变量

  let a = 1, b = 2, c;
  c = a;
  a = b;
  b = c;
  //==> a = 2, b = 1

第二种：借助Object

  let a = 1, b = 2;
  let obj = {
      a: b,
      b: a,
  }
  a = obj.a; b = obj.b;
  //==> a = 2, b = 1

第三种：ES6的赋值解构

  let a = 1, b = 2;
  [a, b] = [b, a];
  //==> a = 2, b = 1