Mongoose Sort a query result on the last element of an array field's value

Question

I have a mongoose schema like this:

    const chatRoomSchema = new mongoose.Schema({
       roomid: String,
       eventid: String,
       users: [String],
       messages: [
        {
          userid: String,
          message: String,
          createdOn: { type: Date, default: Date.now },
        },
      ],
});

I want to query all the chatrooms but I want to sort it on the basis of chatroom which got the latest chat message (chatroom with last createdOn message first).

I know that I can sort on the basis of first message's createdOn by using

Chatroom.find().sort({ "messages.0.createdOn": -1 })

but how could I sort it on the last message?

Answer 1

Chatroom.find().sort({ "messages.createdOn": -1 })

尝试这个 。