New check: useless branches in update

[brianvanburken]

We start developing our Elm files with a Msg containing a branch called NoOp which just returns the model unchanged and most of the time accompanied with Cmd.none. As the development progresses these branches become useless. Below is an SSCE showing an example where NoOp does not have any uses. Removing these kind of branches should clean up code a bit.

module Main exposing (..)

import Html exposing (Html)
import Html.Events as Event


type alias Model =
    Int


model : Model
model =
    0


type Msg
    = NoOp
    | Inc
    | Dec


update : Msg -> Model -> Model
update msg model =
    case msg of
        Inc ->
            model + 1

        Dec ->
            model - 1

        NoOp ->
            model


view : Model -> Html Msg
view model =
    Html.div []
        [ Html.button [ Event.onClick Dec ] [ Html.text "-" ]
        , Html.div [] [ Html.text (toString model) ]
        , Html.button [ Event.onClick Inc ] [ Html.text "+" ]
        ]


main : Program Never Model Msg
main =
    Html.beginnerProgram
        { view = view
        , model = model
        , update = update
        }