class Pick{
    
    constructor(id, i){
         this.aa=id;
         this.kk=i;
    }
    
     
    start(id){
        dlog(''+this.aa);
        this.run(id);
    }
    
    
    run(id){
        
        if(this.kk > 10) return;
        dlog('标记1:'+this.aa+"  "+this.kk+id);//标记1
        thread(function (){
            dlog('标记2:'+this.aa+"  "+this.kk+id);//标记2
            this.kk++;
            this.run(id);
        }, 1000*5);
        
    }

     
}


function dlog(msg){
     console.log(msg);
}

function thread(callBack, time){
    
     setTimeout(function(){
        callBack();
      },  time);
    
    
}

使用

let picker_id = 'test'
let pick = new Pick(picker_id, 0);
pick.start(picker_id);

报错

Uncaught TypeError: Cannot read property 'aa' of undefined

报错的是“标记2”这行代码。一样的代码，”标记1“倒没有报错。线程里面就报错，请问应该如何修改呢？