Work around for Elm Reactor programWithFlags (elm 0.18)

README.md

To work around running a programWithFlags with elm-reactor create a separate application entry point.

In the below example there is App.elm – the main application which uses flags. Reactor.elm will run this this app, but initializes the model with static values to simulate the flags.

App.elm

module App exposing (..)

import Html


type alias Flags =
    { name : String }


type alias Model =
    { name : String }


type Msg
    = None


update : Msg -> Model -> ( Model, Cmd Msg )
update msg model =
    model ! []


init : Flags -> ( Model, Cmd Msg )
init flags =
    Model flags.name ! []


main : Program Flags Model Msg
main =
    Html.programWithFlags
        { init = init
        , view = view
        , update = update
        , subscriptions = subscriptions
        }


view : Model -> Html.Html Msg
view model =
    Html.div [] [ Html.text model.name ]


subscriptions : Model -> Sub Msg
subscriptions model =
    Sub.none

Reactor.elm

module Reactor exposing (..)

import App exposing (..)
import Html


main : Program Never Model Msg
main =
    Html.program
        { init = init { name = "Reactor" }
        , view = view
        , update = update
        , subscriptions = subscriptions
        }