1.数组字符串去重

利用es6的set数据结构特性：成员的值都是唯一的 来完成数组去重

数组去重
let arr = ["1", "2", "3", "2", "5", "1"];
var result =[...new Set(arr)];
console.log(result );  //["1", "2", "3", "5"]

字符串去重
let str = "ababbc";
let result = [...new Set(str)].join("");
console.log(result);  //'abc'

2.获取json的key和value组成的数组

let json = {
      username: "小明",
      age: 18,
      score: "89",
      sex: "男",
};
Object.keys(json);  //["username", "age", "score", "sex"]
Object.values(json);  //["小明", 18, "89", "男"]