Why is it preferable to use the Interactor layer when working with data instead of directly accessing the repository?

Using an Interactor (or Use Case) layer between the UI and the repository allows separating business logic from data storage details. This enhances the modularity and testability of the application, as the Interactor is responsible for specific usage scenarios, and the repository only handles data access.

Advantages:

• Encapsulation of business logic: The Interactor combines data operations without revealing repository details.
• Simplified testing: Business logic can be tested separately by mocking or stubbing the repository.
• Flexibility: When changing the data source (e.g., from local database to network), only the repository changes, while the Interactor remains unchanged.

Example:

class UserInteractor(private val userRepository: UserRepository) {
    fun getUserProfile(userId: String): UserProfile {
        val user = userRepository.getUserById(userId)
        // Additional logic, such as filtering or aggregation
        return UserProfile(user.name, user.age)
    }
}