Single Responsibility Principle (SRP) - SOLID

The SOLID Principles

• 🧱
  Single Responsibility Principle (SRP) - SOLID

• 🧱
  Open-Closed Principle (OCP) - SOLID

• 🧱
  Liskov Substitution Principle (LSP) - SOLID

• Interface Segregation Principle

• Dependency Inversion Principle.

The Single Responsibility Principle (SRP)

Benefits Explained

• Maintainability: A small class is easy to maintain. Having a single responsibility per class results in small classes.

• Classes are easier to understand: The smaller the class the fastest one can go through it and understand it.

• Naming classes: Naming is hard, right? Well if you only have one responsibility you can represent it in the class name. Having more than one responsibility makes it much harder to find a name that represents everything.

Example

BAD

// BAD
class UserSettings {
  constructor(user) {
    this.user = user;
  }

  changeSettings(settings) {
    if (this.verifyCredentials()) {
      // ...
    }
  }

  verifyCredentials() {
    // ...
  }
}

GOOD

// GOOD
class UserAuth {
  constructor(user) {
    this.user = user;
  }

  verifyCredentials() {
    // ...
  }
}

class UserSettings {
  constructor(user) {
    this.user = user;
    this.auth = new UserAuth(user);
  }

  changeSettings(settings) {
    if (this.auth.verifyCredentials()) {
      // ...
    }
  }
}