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name: architecture-patterns description: This skill should be used for system design, design patterns, architectural decisions, SOLID principles, clean code structure, code organization, refactoring strategy, software architecture whenToUse: Architecture design, design patterns, system structure, code organization, refactoring, clean code, SOLID, dependency injection, layered architecture whenNotToUse: Simple implementations, established patterns, trivial changes seeAlso:

• skill: api-design when: designing service APIs
• skill: database-patterns when: data layer architecture
• skill: testing-strategies when: test architecture decisions

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Architecture Patterns

Common architectural patterns and design decisions.

Layered Architecture

Presentation → Business Logic → Data Access → Database

Clean Architecture

        Controllers
             ↓
        Use Cases
             ↓
         Entities

Common Patterns

Repository

interface UserRepository {
    findById(id): User
    save(user): void
}

Service Layer

class UserService {
    constructor(repo: UserRepository)
    createUser(data): User
}

Dependency Injection

• Pass dependencies via constructor
• Program to interfaces, not implementations
• Enables testing with mocks

Design Principles

• SOLID: Single responsibility, Open/closed, Liskov, Interface segregation, Dependency inversion
• DRY: Don't repeat yourself
• KISS: Keep it simple
• YAGNI: You aren't gonna need it