es6的Set太好用了

let mySet = new Set();
//添加  add
mySet.add(1);
mySet.add(5);
mySet.add(5);
mySet.add('some text');
let o = { a: 1, b: 2 };
mySet.add(o);
mySet.add({ a: 1, b: 2 });
//集合中是否存在   has
const has = mySet.has(o);
//删除  delete
mySet.delete(5);
//集合的遍历迭代  for...of
for(let item of mySet) console.log(item);
//集合转数组 [...mySet]   Array.from()
const myArr  = [...mySet]
const myArr = Array.from(mySet);
//数组转集合
const mySet2 = new Set([1,2,3,4]);
//求交集 (ilter() 方法创建一个新的数组，新数组中的元素是通过检查指定数组中符合条件的所有元素)
const intersection = new Set([...mySet].filter(x => mySet2.has(x)));
//求差集
const difference = new Set([...mySet].filter(x => !mySet2.has(x)));