Accessing parent state

[yspreen]

I separate out my app state into nested sub stores. Let's say there's a chat feature, a video feature, and a login feature. What would be a good way to access loginState.currentlyLoggedInUser inside the chat state?

My solution doesn't feel good. I'm storing currentlyLoggedInUser in the root state, and I create all my sub-states as computed properties.

1. the login store gets the user
2. calls the action to set currentlyLoggedInUser
3. root reducer sets the root state
4. now all sub-states (which are computed properties) get the new object like so:

    // inside AppState.swift
    public var chat: ChatState {
        get {
            return ChatState(
                currentlyLoggedInUser: self.currentlyLoggedInUser,
                // ...
            )
        }
    }

what would be a better way to do this?

[JacksonUtsch]

Do the sub-reducers require the the shared state? If only the views require access to the state you can inject properties (Binding for read/write) or callbacks.

If the reducers do require the shared state and are read-only I might be tempted to keep their state separate per domain but then include a parent reducer and .combine it with the main reducer specifically to write/sync the new state when it is set (Syncing reducer of sorts). If you take this route adding tests for this functionality should be taken to assure the behavior and prevent regressions.

If the reducer requires both read and write you can pass the shared state as an inout initializer property.

Not sure if these are ideal solutions either but I think picking the solution with the least possible intrusion is a good goal.

I haven't taken the computed property route but have seen others tend to, seems like it could be tricky to up-keep with added properties and such.