JavaScript Prototype 구조

function Person(name, gender) {
  this.name = name;
  this.gender = gender;
  this.sayHello = function(){
    console.log('Hi! my name is ' + this.name);
  };
}

var foo = new Person('Lee', 'male');

console.dir(Person);
console.dir(foo);

console.log(foo.__proto__ === Person.prototype);                // ① true
console.log(Person.prototype.__proto__ === Object.prototype);   // ② true
console.log(Person.prototype.constructor === Person);           // ③ true
console.log(Person.__proto__ === Function.prototype);           // ④ true
console.log(Function.prototype.__proto__ === Object.prototype); // ⑤ true

참고자료
https://poiemaweb.com/js-prototype#42-%EC%83%9D%EC%84%B1%EC%9E%90-%ED%95%A8%EC%88%98%EB%A1%9C-%EC%83%9D%EC%84%B1%EB%90%9C-%EA%B0%9D%EC%B2%B4%EC%9D%98-%ED%94%84%EB%A1%9C%ED%86%A0%ED%83%80%EC%9E%85-%EC%B2%B4%EC%9D%B8