ECMAScript7新特性

1、array.prototype.includes
判断某一项是否在数组中，直接返回boolean值
let arr = ['aaaa','bbbb','cccc','dddd'];
console.log(arr.includes('aaaa'));

比indexOf判断简单

2、** 替代 Math.pow()
//console.log(2**10)

Math.pow(2,10)
//1024