Hide internal state properties from the UI

[davidscheutz]

Currently all properties of the State model are exposed to the UI.
In some use cases it is helpful to have state values that aren't relevant for the UI.
It would be nice if we could hide those details...

[davidscheutz]

Should the Update object instead hold those internal properties?
What are the consequences of having state "outside" the State model itself?

[davidscheutz]

Thinking in progress

Model

struct ExampleState {
   let uiRelevant: String
   let uiIrrelevant: String
}

Protocol based

protocol ExampleUiState {
    var uiRelevant: String { get }
}

extension ExampleState: ExampleUiState {}

Usage

• Extend Update

public protocol Update {
    associatedtype UIState: AnyObject // reference (class or protocol) constraint
    associatedtype S: Equatable & UIState
    ...
}

extension Update {
    // default value - can it be "overridden"?
    typealias UIState = S
}

• Transform at output

ExampleView.create(
    update: ExampleUpdate.self, 
    uiType: ExampleUiState.self, // new
    effectHandler: ExampleEffectHandler()
)