如何在Firebase中获得排名？

firebase.firestore().collection("players")
    .orderBy("score", "desc")
    .limit(10)
    .get()
    .then((querySnapshot) => {
        querySnapshot.forEach((doc) => {
            console.log(doc.data());
        });
    })
    .catch((error) => {
        console.log("Error getting players: ", error);
    });

firebase.firestore().collection("players")
    .orderBy("score", "desc")
    .startAt(playerScore)
    .limit(1)
    .get()
    .then((querySnapshot) => {
        querySnapshot.forEach((doc) => {
            console.log(doc.data());
        });
    })
    .catch((error) => {
        console.log("Error getting player's rank: ", error);
    });