使用 Firestore 云更新数据 function

Question

I need help, i'm trying to update my comments collections using cloud function, but my code doesn't seem to work. My function succesfully run but doesn't update my avatarUrl when my userPhotoUrl is update

Here the whole path of the collection that i want to update: "/comments/{postId}/comments/{commentId}"

my firestore collection

 exports.onUpdateUser2 = functions.firestore
    .document("/users/{userId}")
    .onUpdate(async (change, context) => {
      const userUpdate = change.after.data();
      const userId = context.params.userId;
      const newPhotoUrl = userUpdate.photoUrl;
      console.log("userId",userId);
      console.log("newPhotoUrl",newPhotoUrl);

    const querySnapshot = await admin.firestore().collection("comments").get();
    querySnapshot.forEach(doc => {
      console.log("doc",doc.data());
      const postId = doc.id;
      const comments = admin.firestore().collection("comments").doc(postId).collection("comments").where("userId","==",userId).get();
      comments.forEach(doc2 => {
        return doc2.ref.update({avatarUrl: newPhotoUrl});
      });
    });
 });

Thank you,

UPDATE

I try to change the code, by using then to deal with these various promises but i don't really know why commentsRef.get() seem to return me empty querySnapshots, because the comments collections in my firestore database have multiple documents where in each documents there is a another comments collections where in this seconds comments collections there is a bunch of documents containing data. With this whole path i don't know how to iterate until being in the documents containing the data that i need to update. Can someone help me please?

exports.onUpdateUserUpdateComments = functions.firestore
        .document("/users/{userId}")
        .onUpdate(async (change, context) => {
          const userUpdate = change.after.data();
          const userId = context.params.userId;
          const newPhotoUrl = userUpdate.photoUrl;
          console.log("userId",userId);
          console.log("newPhotoUrl",newPhotoUrl);
          const commentsRef= admin.firestore().collection("comments");
          return commentsRef.get().then(querySnapshot => {
            return querySnapshot.forEach(doc => {
              return admin
                 .firestore()
                 .collection("comments")
                 .doc(postId)
                 .collection("comments")
                 .where("userId", "==", userId)
                 .get()
                 .then(doc => {
                   if (doc.exists) {
                     doc.ref.update({avatarUrl: newPhotoUrl});
                   }
                   return console.log("The function has been run.");
                 });
            });
          });
     });

Answer 1

Without trying it, it should be something like this:

return admin.firestore().collection("comments")
    .doc(postId)
    .where("userId", "==", userId)
    .get()
    .then(doc => {
        if (doc.exists) {
            doc.ref.update({avatarUrl: newPhotoUrl});
        }
        return console.log("The function has been run.");
    });

Regardless, following Doug Stevenson's advice, you shouldn't start learning JS in Cloud Functions, as those nested loops are a bit strange and you may lack a good starting point for learning.