MongoDB: Cannot use complex condition in subdocument


This Content is from Stack Overflow. Question asked by VladRia

I would like to count all rooms for the particular user with particular roles.

Here is my schema:

const RoomSchema = new Schema({
  moderator: String,

  // Subdocument with two fields *email* and *role*
  participants: {
    type: [{
      _id: false,
      email: {
        type: String,
        index: {
          unique: true,
      role: String,
    default: [],

Here is the query:

  let userEmail = "xxx"

  const result = await RoomModel
      $or: [
        { moderator: userEmail },
          participants: {
            email: userEmail,
            // role: "reader", works fine
            // role: { $in: ["reader"] }, ERROR

Here is the error:

CastError: Cast to string failed for value "{ '$in': [ 'reader' ] }" (type Object) at path "role" for model "Room"

Thank you in advance.


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