Mongoose 过滤器使用或条件

Question

I am creating a chat application using nodejs and mongodb. I need need help retrieving messages between two users. The challenge am facing is I don't know how to filter the chats between two users since a user can be a sender or a recipient.

const messageSchema = new mongoose.Schema({
    content:{type:String, required:true},
    fromUser:{type:mongoose.Schema.Types.ObjectId, ref:'User'},
    toUser:{type:mongoose.Schema.Types.ObjectId, ref:'User'},
    messageRead:{type:Boolean, default:false}
},{
    timestamps:true
})

Answer 1

You can achieve this using $and and $in operators in a match aggregation like this:

db.collection.aggregate([
  {
    $match: {
      $and: [
        {
          fromUser: {
            $in: [
              "user1",
              "user2"
            ]
          }
        },
        {
          toUser: {
            $in: [
              "user1",
              "user2"
            ]
          }
        }
      ]
    }
  }
])

In mongoose if your model is MessageModel your query must be like this:

const messages = await MessageModel.aggregate([...])

Mongodb Playground

Answer 2

I recommend getting the data exactly as you want it:

const userA = new ObjectId('user_a_id');
const userB = new ObjectId('user_b_id');
const messages = await MessageModel.find({
  $or: [
    { fromUser: userA, toUser: userB },
    { fromUser: userB, toUser: userA },
  ]
}).exec();