1. includes
传入元素,如果数组中能找到此元素,则返回 true,否则返回 false
const includeArr = [1, 2, 3, "柯基", "科比"];
const isKobe = includeArr.includes("科比");
console.log(isKobe); // true
跟 indexOf 很像,但还是有区别的
const arr = [1, 2, NaN];
console.log(arr.indexOf(NaN)); // -1 indexOf找不到NaN
console.log(arr.includes(NaN)); // true includes能找到NaN
2. 求幂运算符
以前求幂,需要这么写
const num = Math.pow(3, 2); // 9
ES7 提供了求幂运算符:**
const num = 3 ** 2; // 9