🪨SOLID: 5 Principles of Object Oriented Design

S - Single-responsiblity Principle O - Open-closed Principle L - Liskov Substitution Principle I - Interface Segregation Principle D - Dependency Inversion Principle

1. Single Responsibility Principle(SRP, 단일 책임 원칙)

✅ 모든 class(function,module)은 한 가지 기능을 가지고 있으며 오직 한 가지 이유로만 변화해야 한다. a

• 🚫 SRP 위반 - 변화 가능한 이유가 하나 이상!

class CalorieTracker {
  constructor(maxCalories) {
    this.maxCalories = maxCalories
    this.currentCalories = 0
  }
  // 🚫 track calorie
  trackCalories(calorieCount) {
    this.currentCalories += calorieCount
    if (this.currentCalories > this.maxCalories) {
      this.logCalorieSurplus()
    }
  }
  // 🚫 log calorie
  logCalorieSurplus() {
    console.log("Max calories exceeded")
  }
} 

const calorieTracker = new CalorieTracker(2000)
calorieTracker.trackCalories(500)
calorieTracker.trackCalories(1000)
calorieTracker.trackCalories(700)   // Max calories exceeded

• 🔑 코드를 분리하여 모듈화 - 변화 가능한 이유가 하나씩

// calorie.js
import logMessage from "./log.js"

class CalorieTracker {
  constructor(maxCalories) {
    this.maxCalories = maxCalories
    this.currentCalories = 0
  }

  trackCalories(calorieCount) {
    this.currentCalories += calorieCount
    if (this.currentCalories > this.maxCalories) {
      logMessage("Max calories exceeded")
    }
  }
} 

const calorieTracker = new CalorieTracker(2000)
calorieTracker.trackCalories(500)
calorieTracker.trackCalories(1000)
calorieTracker.trackCalories(700)   // Max calories exceeded

// log.js
export default function logMessage(message) {
  console.log(message)
}

⚙️Reference

Single Responsibility Principle Explained - SOLID Design Principles

The SOLID Principles of Object-Oriented Programming Explained in Plain English