Convert snake case to camel case in Elm

convert_snake_case.elm

convert : String -> String
convert snakeStr =
  let
    repl : Regex.Match -> String
    repl match =
      case List.head match.submatches of
        Just submatch ->
          submatch |> Maybe.withDefault "" |> String.toUpper
        Nothing ->
          Debug.log "error: no submatch" "ERROR"
  in  
    Regex.replace Regex.All (Regex.regex "_([a-z])") repl snakeStr
  
convert2 snakeStr =
  let
    repl : Regex.Match -> String
    repl match =
      case match.submatches of
        [ submatch ] ->
          submatch |> Maybe.withDefault "" |> String.toUpper
        _ ->
          Debug.log "error: not one submatch" "ERROR"
  in  
    Regex.replace Regex.All (Regex.regex "_([a-z])") repl snakeStr


convert3 snakeStr =
  let
    repl match =
      (List.head match.submatches)
        `Maybe.andThen`
        (Maybe.map String.toUpper)
      |> Maybe.withDefault ""
  in
    Regex.replace Regex.All (Regex.regex "_([a-z])") repl snakeStr