How to populate the nested objects in mongoose? - node.js

Question

here's the booking schema
const bookingSchema = new mongoose.Schema({
userId: {
type: mongoose.Schema.Types.ObjectId,
ref: "User",
required: true,
},
routeId:{
type: mongoose.Schema.Types.ObjectId,
ref: "Route",
required: true,
}
})
In this table the routeId(route schema) contains the Bus table(referenced).
const routeSchema = new mongoose.Schema({
location:{
type: mongoose.Schema.Types.ObjectId,
ref: 'Location',
required: true
},
duration: {
type: Number,
required: true
},
Bus:{
type: mongoose.Schema.Types.ObjectId,
ref:"Bus",
required: true
},
date: {
type:String,
required: true
},
},
{
timestamps: true,
});
and then finally the bus model
const busSchema = new mongoose.Schema(
{
busNumber: {
type: String,
unique: true,
required: true,
},
seats: {
type: Number,
},
},
{
timestamps: true,
}
);
Now I want to show only bus number and not whole bus data. this is the response I am getting. https://i.stack.imgur.com/S1qyZ.png
this is the query that I applied.
router.get("/bus/myBooking/one/:id", auth, async (req, res) => {
const _id = req.params.id;
const myBooking = await Booking.findById({ _id })
.populate({path: 'routeId', populate: 'Bus'})
.select(["-_id","-userId","-createdAt","-updatedAt","-__v","-passengers._id","-departureDetails._id","-arrivalDetails._id"]);
try {
return !myBooking
? res.status(404).send("No booking found")
: res.status(200).send(myBooking);
} catch (e) {
res.status(500).send();
}
});

Answer 1

This method works on some versions of mongoose, So you can try this:
await Booking.findById({ _id })
.populate({
path: 'routeId',
populate: {
path: 'Bus',
model: Bus,
select:"-_id busNumber"
}
})