let obj = {

            time: "2017-7-20",
            name: "set",
            _r: 123
        };

let daili = new Proxy (obj, {

                has(target,key){
                if (key==="name"){
                    return target[key];
                }else{
                    return false;
                }
            }
        });    

console.log ("name" in obj,"time" in obj); / / true true should be followed by false