Firestore 在尝试从文档获取数组字段时返回未定义

Question

我正在尝试从此 Firestore 文档中获取

players

数组（您可以在屏幕截图中看到），以便通过 POST 调用更新它。

我的问题是，每当我收到此文档时，调用

doc.data().players

或

doc.get("players")

总是返回未定义。

调试时，我可以看到

doc.data()

包含所有预期的字段和值，所以我不明白为什么我无法获取数组字段，而获取像

doc.data().admin

这样的其他字段却工作正常。

这是我的代码：

export const updatePlayers = async (req, res, next) => {
  try {
    const data = req.body;
    const roomsRef = db.collection("rooms");
    const snapshot = await roomsRef.where("roomId", "==", data.roomId).get();
    const player = req.body.player;
    if (snapshot.empty) {
      console.log("No matching documents.", data.roomId);
      res.status(201).send();
      return;
    }
    console.log("updating players...");

    snapshot.forEach((doc) => {
      const prevPlayers = doc.data().players;
      console.log(doc.data().players, "previous players");
      const newPlayers = [...prevPlayers, player];
      console.log(newPlayers, "new players");
      doc.ref.update({
        players: newPlayers,
      });
      res.status(200).send();
      console.log("players update");
    });
  } catch (error) {
    res.status(400).send(error.message);
  }
};

您发现该方法有什么问题吗？我应该如何获得该字段？

Answer 1

尝试这个版本：

export const updatePlayers = async (req, res, next) => {
  try {
    const data = req.body;
    const roomsRef = db.collection("rooms");
    const snapshot = await roomsRef.where("roomId", "==", data.roomId).get();
    const player = req.body.player;
    
    if (snapshot.empty) {
      console.log("No matching documents.", data.roomId);
      res.status(201).send();
      return;
    }

    console.log("updating players...");
    let updatePromises = [];

    snapshot.forEach((doc) => {
      const docData = doc.data();
      console.log("Document data:", docData);
      
      if (!docData.hasOwnProperty('players')) {
        console.log("Players field does not exist in document.");
        res.status(400).send("Players field not found.");
        return;
      }

      const prevPlayers = Array.isArray(docData.players) ? docData.players : [];
      const newPlayers = [...prevPlayers, player];
      console.log("previous players:", prevPlayers);
      console.log("new players:", newPlayers);

      updatePromises.push(doc.ref.update({
        players: newPlayers,
      }));
    });

    await Promise.all(updatePromises);
    res.status(200).send();
    console.log("players update");
  } catch (error) {
    res.status(400).send(error.message);
  }
};