Mongoose - Cannot modify field value - node.js

Question

I am building a simple shop backend for practice purposes. I have three schemas Product, Customer and Order.
What I am trying to achieve is to subtract the ordered quantity from the stock quantity for each product inside an order, when the order is created. Clearly I am doing something wrong cause my productsToUpdateInDbArray contains the correct products (checked it with console log) but I can't find a way to make it work.
stockQty field inside Products collection is not updating.
My controller code is:
'use strict'
// require validator for string validation
const validator = require('validator');
// import Order, Customer, Product Models
const Order = require("../models/order.model");
const Customer = require("../models/customer.model");
const Product = require("../models/product.model");
// DEFINE CONTROLLER FUNCTIONS
// listAllOrders function - To list all orders
exports.listAllOrders = (req, res) => {
Order.find({}, (err, orders) => {
if (err) {
return res.status(500).send(`Internal server error: ${error}`);
}
if (orders && orders.length === 0) {
return res.status(404).send(`No orders found!`);
}
return res.status(200).json(orders);
});
};
// createNewOrder function - To create new order
exports.createNewOrder = (req, res) => {
const customerId = req.body?.customerId;
const productsArray = req.body?.products;
let productsToUpdateInDbArray = [];
if (!validator.isMongoId(customerId)) {
return res.status(400).send('Invalid customer Id');
}
Customer.findById(customerId, async (err, customer) => {
if (err) {
return res.status(500).send(`Internal server error: ${error}`);
}
if (!customer) {
return res.status(404).send(`No customers found!`);
}
if (!productsArray || productsArray.length === 0) {
return res.status(400).send(`No products found in the order!`);
}
for (let product of productsArray) {
if (!validator.isMongoId(product?.productId)) {
return res.status(400).send('Invalid product Id');
}
if (!product?.quantity || product?.quantity < 1) {
return res.status(400).send('Invalid product quantity');
}
let productFound = await Product.findById(product?.productId).exec();
if (!productFound) {
return res.status(404).send('Product not found!');
}
if (productFound.stockQty < product.quantity) {
return res.status(400).send('Not enough product quantity in stock')
}
productFound.stockQty -= product.quantity;
productsToUpdateInDbArray.push(productFound);
}
console.log(productsToUpdateInDbArray)
const newOrder = new Order(req.body);
newOrder.save((err, order) => {
if (err) {
return res.status(500).send(`Internal server error: ${error}`);
}
for (let item of productsToUpdateInDbArray) {
const filter = { _id: item._id };
const update = { stockQty: item.stockQty };
Product.findOneAndUpdate( filter, update )
}
return res.status(201).json(order);
});
});
};
And my models are:
'use strict';
// Import mongoose
const mongoose = require("mongoose");
// Declare schema and assign Schema class
const Schema = mongoose.Schema;
// Create Schema Instance and add schema propertise
const ProductSchema = new Schema({
name: {
type: String,
required: true
},
price: {
type: Number,
required: true
},
description: {
type: String,
required: true
},
imageUrl: {
type: String,
required: true
},
stockQty: {
type: Number,
required: true
}
});
// create and export model
module.exports = mongoose.model("Products", ProductSchema);
'use strict';
// Import mongoose
const mongoose = require("mongoose");
// Declare schema and assign Schema class
const Schema = mongoose.Schema;
// Create Schema Instance and add schema propertise
const OrderSchema = new Schema({
products: [
{
productId: {
type: Schema.Types.ObjectId,
required: true,
ref: "Products"
},
quantity: {
type: Number,
default: 1
}
}
],
customerId: {
type: Schema.Types.ObjectId,
required: true,
ref: "Customers"
}
});
// create and export model
module.exports = mongoose.model("Orders", OrderSchema);

Answer 1

findOneAndUpdate will only execute the query when a callback is passed. So in your case you can either add an await or callback.
await Product.findOneAndUpdate( filter, update );
or
Product.findOneAndUpdate( filter, update, callback );