Discussion on: The basic Elm example that I wish I'd had

Thanks! <3

I'm by no means an expert in Elm, so it's difficult for me to say for certain (although I'm currently working on a larger Elm application and I'm sure I'll come out of that with more thoughts!), but my current thought on this is that yes, I do prefer the idea of the Model being a Custom Type as opposed to a record. The main thing I kept coming up against when having the model be a record was that it seemed like every separate view ended up having information (or at least theoretical access to information) that it just didn't need - it could very well be that I wasn't organising my models very well, but since making this change in my own code things have felt easier to deal with and reason about.

Again, my thoughts on this in future might change, but as of right now (which is after all when you're asking :D ) I think that this approach is helpful for reasoning about the application itself - if your Model is always describing the state of your application, then it feels likely that this will make life easier for anyone maintaining your application in the future - something I think we should all be careful to consider.

Also, looking at it more carefully... how is the top-level DisplayingRoom type defined? I'm sure that's a ridiculously basic question...

Slight update: After adding navigation into another application, which meant needing to add a navigation key, I've ended up re-evaluating this at the moment. Although all I've done is added any globally-available info to the model, and kept the state the way I described earlier:

-- MODEL


type alias Model =
    { key : Nav.Key
    , state : State
    }


type State
    = ViewSignUp SignUpData
    | ViewLogin LoginData
    | ViewPasswordReset PasswordResetData
    | Loading

And it's still the state that drives the UI itself:

-- VIEW


view : Model -> Document Msg
view model =
    case model.state of
        Loading ->
            { title = "Some app"
            , body = [ loadingView ]
            }

        ViewSignUp data ->
            let
                signUpView =
                    Html.map (\x -> SignUpMsg x) <| SignUp.view data
            in
            { title = "Sign up to Some app"
            , body = [ signUpView ]
            }

        ViewLogin data ->
            let
                loginView =
                    Html.map (\x -> LoginMsg x) <| Login.view data
            in
            { title = "Log in to Some app"
            , body = [ loginView ]
            }

        ViewPasswordReset data ->
            let
                forgottenPasswordView =
                    Html.map (\x -> PasswordResetMsg x) <| PasswordReset.view data
            in
            { title = "Request a password reset"
            , body = [ forgottenPasswordView ]
            }