Proxy

<script type="text/javascript">
    /*
        Proxy  代理，拦截
     */
    let o= {
        a:1,
        b:2
    }
    let obj = new Proxy(o,{
        //get()获取
        get(target,key){//target 目标对象 key 键
            console.log(target);
            console.log(key)
        },
        //set()设置拦截
        set(){}
    })
    console.log(obj.a)
    
</script>