Elm 0.18 Add to list

tweet.elm

module Main exposing (..)

import Html exposing (..)
import Html.Attributes exposing (..)
import Html.Events exposing (..)

type alias Model =
  { tweets : List String
  , new_tweet : String
  }

model : Model
model =
  Model [] ""

type Msg
    = Tweet 
    | ChangeTweet String

update : Msg -> Model -> (Model)
update msg model =
    case msg of
        Tweet ->
            { model | tweets = model.tweets ++ [model.new_tweet] }
        ChangeTweet x ->
            { model | new_tweet = x}

main : Program Never Model Msg
main =
  Html.beginnerProgram {
      model = model
    , view = view
    , update = update 
    }
  
view : Model -> Html Msg
view model =
    div []
        [ div []
                [ input [ type_ "text", onInput ChangeTweet] []
                , button [ onClick Tweet ] [ text "Tweet" ]
                , tweetListing model
              ]
        ]

tweetListing : Model -> Html Msg
tweetListing model =
    div [ ] [ text "tweets shown here" 
    , ul [] (List.map singleTweet model.tweets)]

singleTweet : String -> Html Msg
singleTweet t =
    li [] [text t]