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Implementing Code

implementing-code

Write clean, efficient, maintainable code. Use when implementing features, writing functions, or creating new modules. Covers SOLID principles, error handling, and code organization.

SKILL.md

Full skill instructions

Implementing Code

Workflows

  • Security Check: Injection flaws, auth issues, sensitive data exposure
  • Performance Check: N+1 queries, memory leaks, inefficient algorithms
  • Readability Check: SOLID principles, naming conventions, comments
  • Testing Check: Edge cases, error paths, happy paths

Feedback Loops

  1. Implement feature or fix
  2. Run local tests (unit/​integration)
  3. Run linter/​formatter
  4. If failure, fix and repeat

Reference Implementation

SOLID Compliant Class (TypeScript)

// Abstraction (Interface Segregation)
interface ILogger {
  log(message: string): void;
}

interface IUserRepository {
  save(user: User): Promise<void>;
}

// Domain Entity
class User {
  constructor(public readonly id: string, public readonly email: string) {}
}

// Implementation (Single Responsibility)
class UserService {
  constructor(
    private readonly userRepository: IUserRepository,
    private readonly logger: ILogger
  ) {}

  public async registerUser(email: string): Promise<User> {
    if (!email.includes('@')) {
      throw new Error("Invalid email format");
    }

    const user = new User(crypto.randomUUID(), email);
    await this.userRepository.save(user);
    this.logger.log(`User registered: ${user.id}`);

    return user;
  }
}

Code Review Checklist

  • No hardcoded secrets or credentials
  • Input validation on all external data
  • Proper error handling with meaningful messages
  • No N+1 query patterns
  • Functions follow single responsibility principle
  • Dependencies injected, not instantiated inline
  • Tests cover happy path and edge cases