如何使用更新对象更新节点而不用 Google Cloud Function 覆盖所有子节点？

Question

我正在使用 Google Cloud 函数更新“Rooms/{pushId}/ins”，该函数从多个“门/{MACaddress}/ins”获取新的 In 数据。 目前的功能是这样的：

exports.updateRoomIns = functions.database.ref('/doors/{MACaddress}').onWrite((change, context) => {
    const beforeData = change.before.val(); // data before the write (data of all the doors child nodes)
    const afterData = change.after.val(); // data after the write (data of all the doors child nodes)
    const roomPushKey = afterData.inRoom; // get the right room
    const insbefore = beforeData.ins;
    const insafter = afterData.ins; // get the after data of only the "ins" node
    console.log(insafter);

    if (insbefore != insafter) {
        const updates = {}; 

“const updates = {}”正上方的行创建一个空对象（稍后）填充，并（稍后）更新“rooms/{roompushkey}/ins”节点...

我认为问题可能出在“更新”常量上，因为每次函数运行时都会将这个对象重新定义为一个整体......

代码继续...

        updates['/rooms/' + roomPushKey + '/ins'] = insafter; // populate the "INS" object with the values taken from the "/doors/{MACaddress/ins"
        return admin.database().ref().update(updates); // do the update
    } else {
    return
    }
});

如果我只有一扇门，这会起作用，但由于我有几扇门具有不同的 Ins 数据，所以每次我更新单个“Door/{MACaddress/Ins”时，整个“Rooms/{pushId}/Ins”被最后更新的门上的任何数据替换...我知道 update 方法应该用于此目的，我有点想保留这个“更新”对象以将数据散开到以后的其他路径。这可能吗？有关如何解决此问题的任何建议？

这是我的数据结构：

root: { 
  doors: {
    111111111111: {
       MACaddress: "111111111111",
       inRoom: "-LBMH_8KHf_N9CvLqhzU", // I will need this value for the clone's path
       ins: {
          // I am creating several "key: pair"s here, something like:
          1525104151100: true,
          1525104151183: true,
       }
    },
    222222222222: {
       MACaddress: "222222222222",
       inRoom: "-LBMH_8KHf_N9CvLqhzU", // I will need this value for the clone's path
       ins: {
          // I am creating several "key: pair"s here, something like:
          2525104157710: true,
          2525104157711: true,
       }
    }
  },
  rooms: {
    -LBMH_8KHf_N9CvLqhzU: {
      ins: {
        // I want the function to clone the same data here:
        1525104151100: true,
        1525104151183: true,
      }
    }
  }

Answer 1

根据我之前对您的相关问题 (How to clone a node to another path based on a reference value from the initial path on Google Cloud Functions?) 的回答进行详细说明，我将修改代码如下：

exports.updateRoom = functions.database.ref('/doors/{MACaddress}').onWrite((change, context) => {
    const afterData = change.after.val(); // data after the write

    const roomPushKey = afterData.inRoom;
    const ins = afterData.ins;

    const updates = {};

    Object.keys(ins).forEach(key => {
        updates['/rooms/' + roomPushKey + '/ins/' + key] = true;
    });

    return admin.database().ref().update(updates);

}).catch(error => {
    console.log(error);
    //+ other rerror treatment if necessary

});

换句话说，不是替换完整的 ins 对象，而是在现有的 ins 节点中添加新的子节点。