The MVVM pattern involves three different components. You should be familiar with two of them:
- Model: This is the same model as in MVC, and it represents knowledge and data.
- View: This is the same as in the MVC pattern; it provides an external representation that is understandable by the user, whether human or machine.
- ViewModel: This is the model for a view (duh!). It represents the whole state of the view, and exposes behaviors.
What about UIViewControllers and NSViewControllers?
They belong to the View layer (think back to the previous chapter). We will inject ViewModels in either the views or the viewControllers.
They belong to the View layer (think back to the previous chapter). We will inject ViewModels in either the views or the viewControllers.