<script type="text/javascript"> let target = { name:"小明", age: 15 } let handler = { get(target, propKey, receive){ if(propKey in target){ console.log("success"); }else{ console.log("error") } return Reflect.get(target, propKey, receive); }, set(target, propKey, value, receiver){ if(propKey=='age'){ if(!Number.isInteger(value)){ throw new TypeError('The age is not an integer'); }else{ console.log("set success"); } }else{ console.log("set success"); } return Reflect.set(target, propKey, value, receiver); }, has(target,proKey){ console.log('handle has'); return proKey in target; } } let pro = new Proxy(target,handler); console.log('name' in pro) console.log('sex' in pro) /*pro.name='李四' pro.age=34 console.log(pro.name) console.log(pro.age)*/ </script>