es6 语法 （Proxy和Reflect 的对比）

Posted 2020-10-11 小角色Byme

{ 

  //原始对象
  let obj={
    time:‘2017-03-11‘,
    name:‘net‘,
    _r:123
  };
  //（代理商）第一个参数代理对象，第二个参数真正代理的东西
  let monitor=new Proxy(obj,{
    // 拦截对象属性的读取
    get(target,key){
      return target[key].replace(‘2017‘,‘2018‘)
    },
    // 拦截对象设置属性
    set(target,key,value){
      if(key===‘name‘){
        //赋值并返回
        return target[key]=value;
      }else{
        //不做操作直接返回
        return target[key];
      }
    },
    // 拦截key in object操作
    has(target,key){
      if(key===‘name‘){
        return target[key]
      }else{
        return false;
      }
    },
    // 拦截delete
    deleteProperty(target,key){
      if(key.indexOf(‘_‘)>-1){
        delete target[key];
        return true;
      }else{
        return target[key]
      }
    },
    // 拦截Object.keys,Object.getOwnPropertySymbols,Object.getOwnPropertyNames
    ownKeys(target){
      return Object.keys(target).filter(item=>item!=‘time‘)
    }
  });

  console.log(‘get‘,monitor.time); //2018-03-11
  //操作
  monitor.time=‘2018‘;
  monitor.name=‘mukewang‘;
  console.log(‘set‘,monitor.time,monitor);//2018-03-11;{time: "2017-03-11", name: "mukewang", _r: 123}

  console.log(‘has‘,‘name‘ in monitor,‘time‘ in monitor);//true;false

  delete monitor.time;
  console.log(‘delete‘,monitor);//{time: "2017-03-11", name: "mukewang", _r: 123}
  //
  delete monitor._r;
  console.log(‘delete‘,monitor);//{time: "2017-03-11", name: "mukewang"}

  console.log(‘ownKeys‘,Object.keys(monitor));//["name", "_r"]

}

{
  let obj={
    time:‘2017-03-11‘,
    name:‘net‘,
    _r:123
  };

  console.log(‘Reflect get‘,Reflect.get(obj,‘time‘));//get 2017-03-11
  Reflect.set(obj,‘name‘,‘mukewang‘);
  console.log(obj);//{time: "2017-03-11", name: "mukewang", _r: 123}
  console.log(‘has‘,Reflect.has(obj,‘name‘));//true
}