High-level design

This section explains the high-level design of the frontend and backend.

Frontend

Application design follows a slightly different version of the Model-View-Controller (MVC) pattern, with the addition of the Actions, Store, State, and Communication layers to simplify the controller layer of the traditional iOS application MVC pattern. All application layers are explained in the following sections.

Models

Plain old model structures. These models do not have any logic and only consist of properties. There are four types of model:

• TodoRequest: This is a struct that is used in backend request calls and conforms to RequestProtocol
• Todo: This is a struct that represents Todo data, and uses the Argo and Curry libraries to decode the object from JSON
• TodoViewModel and TodosViewModel: These structs represent data and are used in views and shown to the user
• TodoLens: These lenses modify the Todo model

All the aforementioned models are immutable value types.

Views

We have two View subclasses...