Two child-parent view patterns

ConfigChild.elm

module ConfigChild exposing (Config, Msg, view)

import Html exposing (Html)
import Html.Events

type Msg
  = LaunchTheNukes
  
type alias Config msg =
  { msg : Msg -> msg
  }

view : Config msg -> Html msg
view config =
  Html.button
    [ Html.Events.onClick (config.msg LaunchTheNukes) ]
    []

ConfigParent.elm

module ConfigParent exposing (Msg, view)

import Html exposing (Html)
import ConfigChild

type Msg
  = ChildMsg ConfigChild.Msg

view : Html Msg
view =
  Html.div []
    [ ConfigChild.view
        { msg = ChildMsg }
    ]

MappingChild.elm

module MappingChild exposing (Msg, view)

import Html exposing (Html)
import Html.Events

type Msg
  = LaunchTheNukes

view : Html Msg
view =
  Html.button
    [ Html.Events.onClick LaunchTheNukes ]
    []

MappingParent.elm

module MappingParent exposing (Msg, view)

import Html exposing (Html)
import MappingChild


type Msg
  = ChildMsg MappingChild.Msg

view : Html Msg
view =
  Html.div []
    [ MappingChild.view
        |> Html.map ChildMsg
    ]