看看某个值在不在这个数组里面,是个完整的数
var array1 = [1, 2, 3];
console.log(array1.includes(2));
// expected output: true
var pets = ['cat', 'dog', 'bat'];
console.log(pets.includes('cat'));
// expected output: true
console.log(pets.includes('at'));
// expected output: false
原文：https://www.cnblogs.com/antyhouse/p/10277322.html