如何实现一个函数 isPlainObject 判断是否为纯对象

{
  a: 3;
}
 
Object.create({ a: 3 });

function isPlainObject(obj: any): boolean {
  if (typeof obj !== 'object' || obj === null) return false
 
  let proto = obj
  while (Object.getPrototypeOf(proto) !== null) {
    proto = Object.getPrototypeOf(proto)
  }
 
  return Object.getPrototypeOf(obj) === proto                                                  }
}

const isPlainObject = (o) =>
  Object.prototype.toString.call(o).slice(8, -1) === "Object";