counter.elm

module Main exposing (main)

import Html exposing (Html, button, div, text)
import Html.Events exposing (onClick)


type alias Model =
    { count : Int }


initialModel : Model
initialModel =
    { count = 0 }


type Msg
    = Increment
    | Decrement


update : Msg -> Model -> Model
update msg model =
    case msg of
        Increment ->
            { model | count = model.count + 1 }

        Decrement ->
            { model | count = model.count - 1 }


view : Model -> Html Msg
view model =
    div []
        [ button [ onClick Increment ] [ text "+1" ]
        , div [] [ text <| toString model.count ]
        , button [ onClick Decrement ] [ text "-1" ]
        ]


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