Repository Pattern
interface UserRepo {
findById(id: string): Promise<User>;
}
class PostgresUserRepo implements UserRepo { ... }
class InMemoryUserRepo implements UserRepo { ... } // testDB 접근을 추상화한 계층. 구현 교체 용이·테스트 편리.
interface UserRepo {
findById(id: string): Promise<User>;
}
class PostgresUserRepo implements UserRepo { ... }
class InMemoryUserRepo implements UserRepo { ... } // test