anchor.diff:  module Main =
   
     type Model =
  -    { Input: string
  -      Messages: string list}
  +    { Input: string }
   
       static member initial =
         #if DEV_HMR
  
positive.code: 
      model', action'
  
    let inline onInput x = onEvent "oninput" (fun e -> x (unbox e?target?value))
    let onEnter succ nop = onKeyup (fun x -> if (unbox x?keyCode) = 13 then succ else nop)
  
    let viewMessage msg =
      div
        []
        [ span
            []
            [ text msg ]
          br []
        ]
  
    let view model =
      div
        []
        [ div
            []
            [ text "Guide"
              ol
                []
                [ li
                    []
                    [ text "Enter your text" ]
                  li
                    []
                    [ text "Press enter or click the button" ]
                  li
                    []
                    [ text "See the message been received and added to the list" ]
                ]
            ]
          input
            [ onInput ChangeInput
              property "value" model.Input
              onEnter SendEcho NoOp ]
          button
            [ onMouseClick (fun _ -> SendEcho) ]
            [ text "Send" ]
          br []
          span
            []
            [ text "Messages received:" ]
          div
            []
            (model.Messages |> List.map(viewMessage))
        ]
  
    let webSocketProducer push =
      webSocket.addEventListener_message(
        Func<_,_>(fun e ->
          push(ReceivedEcho (unbox e.data))
          null
      )
    )
  
    let start node () =
      createApp Model.initial view update
      |> withStartNodeSelector node
      |> withProducer webSocketProducer
      |> start renderer
  
negative.code:       if isNotNull (unbox window?storage) then
          unbox window?storage
        else
          let model = { Input = "" }
          window?storage <- model
          model
        #else
        { Input = "" }
        #endif
  
    // Actions supported by the application
    type Actions =
      | ChangeInput of string
  
    let update (model: Model) action =
      let model', action' =
        match action with
        | ChangeInput s ->
          { model with Input = s } , []
  
      #if DEV_HMR
      // Update the model in storage
  