equal search of populated field

Question

I have problem with populating my OfferSchema.

When I'm trying to get booked offers of current user, I'm getting MissingSchemaError: Schema hasn't been registered for model "offer" error from mongoose.

tenant field populate correctly.

I have tried many ways to fix this problem even from official docs, but no one pass for me. I will appreciate any help, thanks.

My Book Schema

const BookSchema = new Schema({

    tenant: {
        type: Schema.Types.ObjectId,
        ref: 'user'
    },

    ...

    offer: {
        type: Schema.Types.ObjectId,
        ref: 'offer'
    }
});

const BookModel = mongoose.model('books', BookSchema);
module.exports = BookModel;

My Offer Schema

const OfferSchema = new Schema({
    ...

    author: {
        type: Schema.Types.ObjectId,
        required: true,
        ref: 'user'
    }
});

const OfferModel = mongoose.model('offers', OfferSchema);

module.exports = OfferModel;

How i try to get result

const landlord = req.userData.userId;

Book.find().populate('tenant', 'email').populate({
    path: 'offer',
    match: {
        'author': {
            $eq: landlord
        }
    }
}).then(books => {
    res.status(200).json({books: books})
}).catch(err => {
    console.log(err);
    res.status(500).json({error: err.message})
});

Answer 1

I have solved my problem in some different way.

Now I'm search for booked offers of current user like this, hope it would be useful for someone in future.

exports.get_landlord_books = async (req, res) => {
    let offers = await Offer.find( {author: req.userData.userId});

    if (offers) {
        Book.find({
            'offer': { $in: offers}
        }).populate('tenant', 'email').then(books => {
            res.status(200).json({books: books})
        }).catch(err => {
            console.log(err);
            res.status(500).json({error: err.message})
        });
    } else {
        console.log('no booked offers for this user')
    }
};