ViewModelless

ViewModelless is a conceptual design pattern in software development, particularly relevant to user interface (UI) architectures. It proposes a way of structuring applications where the UI directly interacts with data repositories or services, bypassing the traditional ViewModel layer. The core idea is to eliminate the ViewModel as an intermediary, simplifying the application's architecture and potentially reducing boilerplate code.

In a ViewModelless pattern, the View is responsible for fetching and manipulating data. This means UI elements would directly call methods on data access objects or services. This approach contrasts with patterns like Model-View-ViewModel (MVVM) or Model-View-Presenter (MVP), where a ViewModel or Presenter acts as a bridge between the View and the Model, encapsulating presentation logic and data transformation.

Proponents of ViewModelless argue it can lead to a more straightforward codebase, especially for simpler applications. By removing the ViewModel layer, developers might save time on creating and managing these intermediate classes. The logic that would typically reside in a ViewModel, such as data formatting, validation, or state management, would instead be handled directly within the View or delegated to other layers like services.

However, this pattern can also introduce challenges. Placing significant business or presentation logic directly within the View can lead to tightly coupled code, making the View harder to test and maintain. It might also violate the principle of separation of concerns, as the View becomes responsible for more than just UI rendering. The suitability of ViewModelless often depends on the complexity of the application and the specific development team's preferences and established practices.