Using Shared Group Data

// CloudScript/Javascript
const MY_GAME_GROUP_KEYS: Array<string> = ["gameState", "currentPlayerTurn"];
interface PlayerTurnArgs {
    sharedGroupId: string;
    nextPlayerTurn: string;
    turnData: any;
}
handlers.TakePlayerTurn = function (args: PlayerTurnArgs) {
    var getRequest: PlayFabServerModels.GetSharedGroupDataRequest = { SharedGroupId: args.sharedGroupId, GetMembers: true, Keys: MY_GAME_GROUP_KEYS };
    var gameData: PlayFabServerModels.GetSharedGroupDataResult = server.GetSharedGroupData(getRequest);
    CheckValidPlayer(currentPlayerId, args.sharedGroupId, gameData.Members, gameData.Data["currentPlayerTurn"].Value, args.nextPlayerTurn);
    var newGameStateJson = UpdateGameState(args.turnData, gameData.Data["gameState"].Value);
    var updateRequest: PlayFabServerModels.UpdateSharedGroupDataRequest = {
        SharedGroupId: args.sharedGroupId,
        Data: {
            "gameState": newGameStateJson,
            "currentPlayerTurn": args.nextPlayerTurn
        }
    };
    server.UpdateSharedGroupData(updateRequest);
}
function CheckValidPlayer(playFabId: string, sharedGroupId: string, members: Array<string>, currentPlayerTurn: string, nextPlayerTurn: string): void {
    var validCurPlayer = false;
    var validNextPlayer = false;
    for (var m = 0; m < members.length; m++) {
        if (members[m] === playFabId)
            validCurPlayer = true;
        if (members[m] === nextPlayerTurn)
            validNextPlayer = true;
    }
    if (!validCurPlayer || !validNextPlayer) // Take extreme action against a player trying to cheat
    {
        server.BanUsers({ Bans: [{ PlayFabId: playFabId, Reason: "Trying to play a game you don't belong to: " + sharedGroupId }] });
        throw "You have been banned";
    }

    if (playFabId !== currentPlayerTurn)
        // May wish to additionally implement a spam-counter here and potentially take more extreme action for high-spam count
        throw "Not your turn";
}
function UpdateGameState(turnData: any, currentState: string): string {
    // PSEUDO-CODE-STUB: Update the turn-based game state according to the rules of this game
    return JSON.stringify({});
}