Main.elm

import Graphics.Element exposing (show)
import Json.Decode as Json exposing ((:=))


-- MODEL

type alias Model =
  { id: Int
  , label: String
  }


serialized : String
serialized = "{\"id\":1,\"label\":\"foo\"}"


decoder : Json.Decoder Model
decoder =
  Json.object2 Model
    ("id" := Json.int)
    -- Notice instead of label we have a "wrongKey"
    ("wrongKey" := Json.string)

main =
  show (Json.decodeString decoder serialized)