객체 Reference

• https://helloworldjavascript.net/pages/180-object.html

• https://ko.javascript.info/object-basics

• https://ko.javascript.info/object-properties

• https://velog.io/@doondoony/JavaScript-Object#-contents

• 객체 생성

• (https://ko.javascript.info/property-accessors)

• (https://developer.mozilla.org/ko/docs/Web/JavaScript/Reference/Global_Objects/Object/defineProperty)

• (https://wesbin.tistory.com/32)

• 프로토타입과 프로토타입 상속