Adding a field to a nested document in mongoDB node js - node.js

Question

Hello since there is not subcollections in mongodb i have found that you can nest document as an array ! i did that and it worked but what i want is to add a field to that existing array without losing the old ones ! i can do that by fetching the old array and adding the new field to it and returning that array but doing the fetch inside the patch method wouldn't be a good approach ! so is there any other way i can make that happen ?
Modal :
const mongoose = require("mongoose");
const notificationSchema = new mongoose.Schema(
{
notificationType: {
type: String,
required: false,
},
message: { type: String, required: true },
},
{
timestamps: true,
}
);
const userSchema = new mongoose.Schema({
name: {
type: String,
required: true,
},
email: {
type: String,
required: true,
},
passwordHash: {
type: String,
required: true,
},
phone: {
type: String,
required: true,
},
isAdmin: {
type: Boolean,
default: false,
},
street: {
type: String,
default: "",
},
notifications: [notificationSchema],
apartment: {
type: String,
default: "",
},
zip: {
type: String,
default: "",
},
city: {
type: String,
default: "",
},
country: {
type: String,
default: "",
},
});
exports.User = mongoose.model("User", userSchema);
exports.Notification = mongoose.model("Notification", notificationSchema);
router.patch("/:id", async (req, res) => {
try {
console.log("hh");
const user = await User.findByIdAndUpdate(req.params.id, {
notifications: [
{
notificationType: "Order",
message: "New Notification",
},
],
});
if (!user) {
return res.status(404).send("The user cannot be found");
}
res.send(user);
} catch (error) {
return res.status(400).json({ success: false, error });
}
});