includes问题

当数组有空的值的时候，includes会认为空的值是undefined，而indexOf不会

let arr = new Array(3);
console.log(arr.indexOf(undefined));//-1   
console.log(arr.includes(undefined));//true 

所以当用includes判断一个空值时最好加一个且运算，被判断的值不为空

 :class="{ activeTag: departmentName.includes(keywords) && keywords != '' }"