1、Object.getPrototypeOf(obj)
该方法返回 obj 对象的原型对象,等同于 obj.__proto__
function Person(){ this.name = 'jack' } let man = new Person(); console.log(Object.getPrototypeOf(man) === Person.prototype); //true console.log(Object.getPrototypeOf(man) === man.__proto__); //true