Näkymämalli

Näkymämalli, often translated as "view model" in English, is a concept used in software development, particularly within the Model-View-Controller (MVC) architectural pattern and its variations like Model-View-ViewModel (MVVM). Its primary purpose is to act as an intermediary between the underlying data model and the user interface (view). The näkymämalli encapsulates the data and logic specifically required by a particular view, presenting it in a format that the view can easily consume and display.

The benefits of using a näkymämalli include improved separation of concerns, making the code more organized and maintainable. By isolating view-specific logic and data, it prevents direct manipulation of the data model by the view, which can lead to inconsistencies. This abstraction also simplifies the view's code, as it doesn't need to worry about complex data transformations or business logic. Instead, it can focus solely on presenting the data provided by the näkymämalli.

In essence, the näkymämalli transforms or prepares data from the domain model into a format suitable for presentation. This might involve filtering, sorting, formatting, or combining data from multiple sources. Developers often create separate näkymämalli classes for different views or even different states of the same view, ensuring that each view receives precisely the information it needs without unnecessary overhead. This pattern is especially prevalent in modern front-end frameworks that emphasize declarative UI development.