Mongoose Populate ignored for this basic setup - mongodb

Question

I have a User Schema, which has multiple notes, and the Note which belongs to a userId
const UserSchema = new Schema({
_id: Schema.Types.ObjectId,
email: {type: String, required: true, trim: true, lowercase: true, unique: true},
notes: [{type: Schema.Types.ObjectId, ref: 'Note'}]
});
const NoteSchema = new Schema({
userId: {type: mongoose.Types.ObjectId, ref: 'User'},
content: {type: String, required: true, trim: true, lowercase: true},
});
I'm trying to populate my User with the notes using the following syntax (from the docs)
const user = await User.findById(mongoose.Types.ObjectId("5bd2a8c4963ac00f57a18074"))
.populate('notes')
.exec(function (err, result) {
console.log(result);
});
But it's returning the User without the Notes data. Any idea what I might be doing wrong?

Answer 1

NoteSchema here is the problem:
userId: {type: mongoose.Types.ObjectId, ref: 'User'}
Use below,
userId: {type: mongoose.Schema.Types.ObjectId, ref: 'User'}
// OR
userId: {type: Schema.Types.ObjectId, ref: 'User'}
// OR
userId: {type: Schema.ObjectId, ref: 'User'} // For backword compatibility
Note:- The schema should always use mongoose.Schema.Types. And mongoose.Types.ObjectId can be used withing mongoose implementation.
I am able to get document properly (Below code):
var mongoose = require('mongoose'),
Schema = mongoose.Schema;
const NoteSchema = new Schema({
userId: {type: Schema.Types.ObjectId, ref: 'UserTest'},
content: {type: String, required: true, trim: true, lowercase: true},
});
const UserSchema = new Schema({
_id: Schema.Types.ObjectId,
email: {type: String, required: true, trim: true, lowercase: true, unique: true},
notes: [{type: Schema.Types.ObjectId, ref: 'NoteTest'}]
});
var Note = mongoose.model('NoteTest', NoteSchema);
var User = mongoose.model('UserTest', UserSchema);
User.find({_id : mongoose.Types.ObjectId("5bd2c84dd79cc5d8b1c62964")})
.populate('notes')
.exec(function (err, result) {
console.log("result.....", JSON.stringify(result));
});
Output:
[
{
"_id": "5bd2c84dd79cc5d8b1c62964",
"email": "hardik#com.com",
"notes": [
{
"_id": "5bd2c869d79cc5d8b1c62965",
"content": "ABC",
"userId": "5bd2c84dd79cc5d8b1c62964"
},
{
"_id": "5bd2c88ad79cc5d8b1c62966",
"content": "DEF",
"userId": "5bd2c84dd79cc5d8b1c62964"
}
]
}
]