Presenter first (software approach)

Presenter first is a software development approach, primarily used in user interface (UI) design and development. It prioritizes the creation and definition of the "presenter" component before the view or model components. This contrasts with approaches like Model-View-Controller (MVC) where often the model is considered first, or Model-View-Presenter (MVP) where a strong dependency often exists between the View and Presenter.

In the presenter first approach, the presenter acts as an intermediary between the model (data) and the view (UI). It encapsulates the presentation logic, formatting data for display, and handling user interactions. The key characteristic of this approach is that the presenter is developed as an independent, testable unit before being connected to the view. This allows for clearer separation of concerns, enhanced testability, and potential for view swapping or adaptation.

The presenter typically defines an interface that the view must implement. This interface specifies the methods the view exposes for the presenter to interact with, such as setting data or triggering UI updates. By defining the view's contract upfront, the presenter can be developed and tested in isolation, using mock views for testing purposes. Once the presenter is robust, the actual view can be implemented according to the defined interface.

Benefits of presenter first include:

• Improved Testability: Presenters can be thoroughly tested in isolation using mock views.
• Clear Separation of Concerns: The presenter is responsible solely for presentation logic, leading to cleaner code and easier maintenance.
• View Agnosticism: The presenter is not tightly coupled to a specific view implementation, allowing for view swapping or adaptation to different platforms or UI frameworks.
• Parallel Development: The presenter and view can be developed independently, potentially speeding up the development process.

While beneficial, the presenter first approach might require more upfront design and abstract thinking. It's suitable for complex UIs where testability and maintainability are critical.