Anti-Patterns

// BAD: Using Express in domain
import { Request, Response } from 'express';
class CreateUserCommand {
  execute(req: Request, res: Response) { ... }
}

// BAD: Reading env vars in BC
const apiKey = process.env.API_KEY;

// BAD: Importing from another BC
import { OrderAggregate } from '../order/domain/aggregates';

// BAD: Price calculation in repository
async findWithDiscount(id: string): Promise<Product> {
  const product = await this.db.find(id);
  product.price = product.price * 0.9;  // BAD!
  return product;
}

// BAD: Persistence should NOT implement port
class UserPersistence implements UserRepositoryOutboundPort { ... }

// GOOD: Only implementations/ use `implements`
class UserRepository implements UserRepositoryOutboundPort {
  constructor(private persistence: UserPersistence) {}
}

// BAD: Custom logic in guard
async guard(request: Request): Promise<GuardResult> {
  const discount = request.user.isVIP ? 0.2 : 0;  // BAD!
  return { allowed: true, discount };
}

// BAD: Calculation in mapper
function toResponse(order: Order): OrderResponse {
  return {
    ...order,
    total: order.items.reduce((sum, i) => sum + i.price, 0),  // BAD!
  };
}

// BAD: BC importing from Infrastructure
import { DrizzleUserRepository } from '@infra/repositories';

// BAD: Module A imports Module B, AND Module B imports Module A
// This creates circular dependency

// BAD: Missing port suffix
interface UserRepository { ... }

// GOOD
interface UserRepositoryOutboundPort { ... }