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New skills (14): - nestjs-best-practices: 40 priority-ranked rules (kadajett) - fastapi: Pydantic v2, async SQLAlchemy, JWT auth (jezweb) - architecture-patterns: Clean Architecture, Hexagonal, DDD (wshobson) - python-performance-optimization: Profiling and optimization (wshobson) - ai-sdk: Vercel AI SDK streaming and agent patterns (vercel) - create-agent: Modular agent architecture with OpenRouter (openrouterteam) - proactive-agent: WAL Protocol, compaction recovery, self-improvement (halthelobster) - brand-guidelines: Brand identity enforcement (anthropics) - ui-animation: Motion design with accessibility (mblode) - marketing-ideas: 139 ideas across 14 categories (coreyhaines31) - pricing-strategy: SaaS pricing and tier design (coreyhaines31) - programmatic-seo: SEO at scale with playbooks (coreyhaines31) - competitor-alternatives: Comparison page architecture (coreyhaines31) - referral-program: Referral and affiliate programs (coreyhaines31) README reorganized by domain: Code Quality, Frontend, Backend, Auth, AI/Agent Building, Marketing, Design, Meta. Mosaic Stack is not limited to coding — the Orchestrator serves coding, business, design, marketing, writing, logistics, and analysis. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
2.8 KiB
2.8 KiB
title, impact, impactDescription, tags
| title | impact | impactDescription | tags |
|---|---|---|---|
| Use Repository Pattern for Data Access | HIGH | Decouples business logic from database | architecture, repository, data-access |
Use Repository Pattern for Data Access
Create custom repositories to encapsulate complex queries and database logic. This keeps services focused on business logic, makes testing easier with mock repositories, and allows changing database implementations without affecting business code.
Incorrect (complex queries in services):
// Complex queries in services
@Injectable()
export class UsersService {
constructor(
@InjectRepository(User) private repo: Repository<User>,
) {}
async findActiveWithOrders(minOrders: number): Promise<User[]> {
// Complex query logic mixed with business logic
return this.repo
.createQueryBuilder('user')
.leftJoinAndSelect('user.orders', 'order')
.where('user.isActive = :active', { active: true })
.andWhere('user.deletedAt IS NULL')
.groupBy('user.id')
.having('COUNT(order.id) >= :min', { min: minOrders })
.orderBy('user.createdAt', 'DESC')
.getMany();
}
// Service becomes bloated with query logic
}
Correct (custom repository with encapsulated queries):
// Custom repository with encapsulated queries
@Injectable()
export class UsersRepository {
constructor(
@InjectRepository(User) private repo: Repository<User>,
) {}
async findById(id: string): Promise<User | null> {
return this.repo.findOne({ where: { id } });
}
async findByEmail(email: string): Promise<User | null> {
return this.repo.findOne({ where: { email } });
}
async findActiveWithMinOrders(minOrders: number): Promise<User[]> {
return this.repo
.createQueryBuilder('user')
.leftJoinAndSelect('user.orders', 'order')
.where('user.isActive = :active', { active: true })
.andWhere('user.deletedAt IS NULL')
.groupBy('user.id')
.having('COUNT(order.id) >= :min', { min: minOrders })
.orderBy('user.createdAt', 'DESC')
.getMany();
}
async save(user: User): Promise<User> {
return this.repo.save(user);
}
}
// Clean service with business logic only
@Injectable()
export class UsersService {
constructor(private usersRepo: UsersRepository) {}
async getActiveUsersWithOrders(): Promise<User[]> {
return this.usersRepo.findActiveWithMinOrders(1);
}
async create(dto: CreateUserDto): Promise<User> {
const existing = await this.usersRepo.findByEmail(dto.email);
if (existing) {
throw new ConflictException('Email already registered');
}
const user = new User();
user.email = dto.email;
user.name = dto.name;
return this.usersRepo.save(user);
}
}
Reference: Repository Pattern