Because model is such a common name to use in your update function, it can be tricky to ensure you’re always using the most updated version. Whether it is model_, model2, or updatedModel, subtle bugs can work their way into your code if you use the wrong one.
You can almost completely eliminate that problem if you use the pipe operator |> and never bind anything. The Update.Extra module makes that easy.
Examples
Main.elm
update : MsgDetail -> Model -> ( Model, Cmd Msg )
update msg model =
case msg of
Edit listId id name ->
Lists.update (Create listId) model
|> Tuple.mapFirst (updateDetail id name)
|> Update.addCmd (writeToLocalStorage name)
|> andThen Server.update Save
andThen : (msg -> model -> ( model, Cmd a )) -> msg -> ( model, Cmd a ) -> ( model, Cmd a )
andThen update msg ( model, cmd ) =
let
( model_, cmd_ ) =
update msg model
in
( model_, Cmd.batch [ cmd, cmd_ ] )
Links