Firebase Cloud Functions - 实时数据库 - 获取父节点密钥

Question

我正在尝试从快照中获取父节点的密钥。为了确认，当我打印snapshot.val() 时，我从下面的函数中获取了正确的节点数据，所以问题不在于查询，但我似乎找不到获取返回快照密钥的方法。

/games
   |--{game_id} ==> get this id
         |---"alias":"123456" ==> from the snapshot returned by querying this
         |---"players":...
         |..... // other childs of game_id

这里是云函数代码：

export const getGameIDFromCode = functions.https.onCall((data, context) => {

    if (context.auth == null) {
        throw new functions.https.HttpsError('permission-denied', 'You are not authorized to use this feature');
    }

    const code = data.code;
    const gamesRef = db.ref("/games");
    return gamesRef.orderByChild("alias").equalTo(code).once("value").then(snapshot => {

        if (snapshot.ref.parent != null) {
            // tried snapshot.key => returns "games"
            // tried snapshot.ref.key ==> returns "games"
            return snapshot.ref.parent.key;
        } else {
            return "Unable to find game_id for the code";
        }


    }).catch(error => {
        return error;
    });


});

Answer 1

将代码更改为可以工作：

 return gamesRef.orderByChild("alias").equalTo(code).limitToLast(1).once("value").then(snapshot => {

        let gameId;

        snapshot.forEach(child => {
            gameId = child.key;
        })

        return gameId;

    }).catch(error => {
        return error;
    });