ES7语法特性 includes **幂运算

ES7

数组方法 includes

includes 检测数组中是否包含某个元素，返回布尔类型

indexOf方法，存在返回索引，不存在返回-1

      let arr = [1, 11, 22, 33, 44, 55, 66];console.log(arr.indexOf(33)); // 3console.log(arr.indexOf(333)); // -1

includes

      let arr = [1, 11, 22, 33, 44, 55, 66];console.log(arr.includes(33)); // trueconsole.log(arr.includes(333)); // false

** 幂运算

	console.log(2 ** 10); // 1024

与 Math.pow(2, 10) 效果一样

    console.log(Math.pow(2, 10)); // 1024