Repository contracts

Abstract repository classes and query DTOs in the domain.

The domain layer defines what the repository should do, without exposing how data is persisted. Handlers depend on these contracts; infrastructure provides concrete implementations.

Abstract class

typescript

// src/domain/repositories/iperson.repository.ts
import { ListResponse } from '@/core/types';
import { PersonQueryDto } from '../dtos/person-query.dto';
import { Person } from '../entities/person/person';

export abstract class IPersonRepository {
  abstract findMany(query: PersonQueryDto): Promise<ListResponse<Person>>;
  abstract findById(id: number): Promise<Person | null>;
  abstract save(person: Person): Promise<Person>;
  abstract delete(person: Person): Promise<void>;
}

Query DTO

Query DTOs live in src/domain/dtos and extend PaginationDto when applicable:

typescript

export class PersonQueryDto extends PaginationDto {
  @AutoMap()
  name?: string;
}

The handler maps the validated request to the DTO before calling the repository:

typescript

const query = AutoMapper.map(
  new ReadManyPersonValidator(req).validate(),
  ReadManyPersonRequest,
  PersonQueryDto,
);

Injection in the handler

Handlers receive the abstract class via constructor:

typescript

@Injectable()
export class DeletePersonHandler implements RequestHandlerBase<number, void> {
  constructor(private readonly repository: IPersonRepository) {}

  async handle(id: number): Promise<void> {
    const person = await this.repository.findById(id);

    if (!person) {
      throw new NotFoundException('Pessoa não encontrada');
    }

    await this.repository.delete(person);
  }
}

Binding in the infrastructure module

typescript

@Module({
  imports: [DatabaseModule],
  providers: [{ provide: IPersonRepository, useClass: PersonRepository }],
  exports: [DatabaseModule, IPersonRepository],
})
export class RepositoryModule {}

Creating a new repository

Define the abstract class in src/domain/repositories/i<resource>.repository.ts.
Create the query DTO in src/domain/dtos/ if there are filtered listings.
Implement the concrete class in src/infra/repositories/.
Register the provider in RepositoryModule.