1、``反引号
eg：let a = "world";
`hello ${a} ！` 输出为 hello world ！
2、=>箭头函数
eg: (x,y) => x+y;
(x,y) => {return x+y;}
3、数组新功能
1）定义
eg: let [a, b, c] = [1, 2, 3]
console.log(a,b,c)//输出值为1,2,3
2）...
let arr = [2,3,4]
let arr2 = [1, ...arr, 5]
console.log(arr2)//输出值为1,2,3,4,5
3）includes
let a = [1,2,3];
console.log( a.includes(2)) //输出值为true
4）map
let a = [1, 3, 5];
let b = a.map((i) => i+1);
console.log(b) //输出值为2,4,6
