decoding an array

Types.re

type userId = string;
type gameId = string;
type screenName = string

type player = {
  userId,
  screenName  
};

type serverGameState = 
  | Waiting
  | Started;

type serverGame = {
  id: gameId,
  owner: player,
  players: array(player),
  state: serverGameState  
};

type serverGames = array(serverGame);

type gamesUpdate = {
  games: serverGames
}

module Decode = {
  let player = (json) => 
    Json.Decode.(
      {
        userId: json |> field("user_id", string),
        screenName: json |> field("screen_name", string)
      }
    );
  
  let gameState = 
      fun 
      | "waiting" => Waiting
      | "started" => Started
      | _ => Waiting;
      
  let serverGame = (json) => 
    Json.Decode.(
      {
        id: json |> field("id", string),
        owner: json |> field("owner", player),
        players: json |> array(field("players", player)),
        state: json |> field("state", string) |> gameState
      }
    );
  
  let gamesUpdate = (json) => {  
    Js.log(Js.Json.stringify(json));
    /* {"games":[{"state":"waiting","players":[{"user_id":"hello","screen_name":"screeeen"}],"owner":{"user_id":"hello","screen_name":"screeeen"},"id":"this_is_a_game"}]} */
    Json.Decode.(
      { games: json |> field("games", array(serverGame)) }
    )
  }
}

/*

"Expected array, got {"state":"waiting","players":[{"user_id":"hello","screen_name":"screeeen"}],"owner":{"user_id":"hello","screen_name":"screeeen"},"id":"this_is_a_game"}
	in array at index 0
	at field 'games'"
  
*/