Push an item into an array type in mongo db through mongoose

mongoose_array_push_example.js

let options = { "upsert": true, "new": true };
let update = { "$push": { } };
update["$push"]["receipts"]  = url;
Tran.findByIdAndUpdate(id, update, options, function(err, tran) {
    if (err) {
        res.status(500).json({ error: err.message })
    } else {
        res.status(200).json({ message: 'Item pushed successfully.' });
    }