MongoDB geting an empty array from an aggregation - node.js

Question

So I created this controller to get me the sum of all the orders totalPrice made by months
const getMonthlyOrderTotal = async (req, res) => {
try {
const year = req.params.year;
const aggregatePipeline = [
{
$match: {
createdAt: {
$gte: new Date(`${year}-01-01T00:00:00.000`),
$lt: new Date(`${year}-12-31T23:59:59.999`)
}
}
},
{
$group: {
_id: {
$month: "$createdAt"
},
total: {
$sum: "$totalPrice"
}
}
},
{
$sort: {
_id: 1
}
}
];
const orderTotals = await Order.aggregate(aggregatePipeline);
res.json(orderTotals);
} catch (err) {
res.status(500).json({ message: err.message });
}
};
this is the orderModel I am using
import mongoose from "mongoose";
const orderSchema = mongoose.Schema(
{
user: {
type: mongoose.Schema.Types.ObjectId,
required: true,
ref: "User",
},
client: {
type: mongoose.Schema.Types.ObjectId,
required: true,
ref: "Client",
},
orderItems: [
{
name: { type: String, required: true },
qty: { type: Number, required: true },
image: { type: String },
price: { type: Number, required: true },
product: {
type: mongoose.Schema.Types.ObjectId,
required: true,
ref: "Product",
},
},
],
totalPrice: {
type: Number,
required: true,
default: 0.0,
},
taxPrice: {
type: Number,
required: true,
default: 0.0,
},
isPaid: {
type: Boolean,
required: true,
default: false,
},
paidAt: {
type: Date,
},
isDelivered: {
type: Boolean,
required: true,
default: false,
},
deliveredAt: {
type: Date,
},
},
{
timestamps: true,
}
);
const Order = mongoose.model("Order", orderSchema);
export default Order;
and when I try to test this API in postman "http://localhost:5001/orders/orderstotal/2022" I always get an empty array even though there is stored data in mongoDB orders Collection