为什么显示结果不对呢

[Sleet]

回复: #50 实现 js 数据类型的判断
控制台都试了试木有问题呀

    const type = (obj)=> {
      let typeObj = typeof obj;
      if(typeObj == 'object'){
        //先看看是不是null
        if(obj === null){
          return null
        }else{
          let prototypeObj = Object.getPrototypeOf(obj)
          let prototypeObjConstructor = prototypeObj.constructor.name.toLowerCase();
          return  prototypeObjConstructor;
        }
      }
      return typeObj;
    }