Vue(定时器)解决mounted不能获取到data中的数据问题

 data() {
  return {
  isok:10,
}
}
 

mounted(){
 
 console.log(this.isok)  //能获取isok 10
 setInterval(function(){
 console.log(this.isok) //不能获取 isok
}, 3000);
 
}

 mounted(){
 setInterval(()=>{ consolog.log(this.isok) }, 3000);
 }

 mounted(){
  var that=this;
  setInterval(()=>{
  console.log(that.isok)
  }, 3000);
 }

<div id="app">
   <ul>
    <li v-for="(stu,index) in students1">{{stu}}</li>
   </ul>
  </div>
  <script type="text/javascript">
   new Vue({
    el:"#app",
    data:{
     students:[
      {name:"小a",age:20},
      {name:"小b",age:21},
      {name:"小c",age:18},
      {name:"小d",age:19},
      {name:"小f",age:18}
     ]
    },
    computed:{
     students1:function(){
      return sortKey(this.students,'age')
     }
    }
   })
   function sortKey(array,key){
    return array.sort(function(a,b){
     var x = a[key];
     var y = b[key];
     return ((x<y)?-1:(x>y)?1:0)
    })
   }
  </script>