JavaScript - OOP

OOP = Object Oriented Programming
"사람이 세계를 보고 이해하는 방법을 흉내낸 방법론"

Computer Programming
The 3 Major families of languages are

• Machine Languages
• Assembly Languages
• High-level Languages <- 자바스크립트가 여기 속함

Machine Languages

• comprised of 1s and 0s
• The 'native' languages of a computer
• Difficult to program
  • one misplaced 1 or 0 will cause the program to fail

Assembly Languages

• Assembly languages are a step towrards easier programming
• Assembly languages are comprised of a set of elemental commands which are tied to a specific processor
• Assembly language code needs to be translated to machine language before the computer processes it

High-Level Languages

• The syntax of HL languages is similar to English

• Interpreter - Executes high level language programs without complilation

• Historically, we divide HL languages into two groups

  • procedural languages
  • Object-oriented languages(OOP) (객체지향 언어)

  

---

Procedural Languages(절차지향 언어)

• Early high-level languages are typically called procedural languages
• Procedural languages are characterized by sequential sets of linear commands. The focus of such languages is on structure
• Example include C, COBOL, Fortran, LISP, Perl, HTML, VBScript

Object-Oriented Languages(객체지향 언어)

• Programmers code using 'blueprints'of data models called classes
• Examples of OOP languages include
  • Java, C++, C#, Python, PHP, JavaScript, Ruby, Perl, Object Pascal, Objective-C, Dart, Swift, Scala, Common Lisp
    -Javascript <<= 초기에는 그다지 아니었으나, 변화를 거치면서 객체지향에 가까워졌음.

---

What is OOP?

• OOP is mainly a program design philosophy
• OOP use a adifferent set of programming languages than old procedural programming languages (C, Pascal, etc)
• Everything in OOP is grouped as self-sustainable "objects". Hence, you gain re-usability by means of four main object-oriented programming concepts.

Classes and Objects

• A class is a prototype, idea and blueprint for creating objects
• An object is an instance of a class
• A class has a constructor for creating objects
• attributes of properties
• method

Encapsulation

• wrapping up of data and function together, into a single unit
• Hide Implementation and Expose behavior
• Loose Coupling: Modify the implementation anytime
  

아래는 Encapsulation의 예시.
노란박스는 절차지향, 초록박스는 노란박스를 객체지향으로 바꾼 것

Inheritance

Abstraction

Polymorphism
의미: many+form = 여러가지 형태


Without Polymorphism

switch(...) {
  case 'select': renderSelect();
  case 'text': renderTextBox();
  case 'checkbox': renderCheckBox();
  case ...
  case ...
  case ...
}

결론: OOP의 장점

강의: 유튜브 javascript-OOP