Order.ts

import { Schema, model } from 'mongoose'
import { IProduct } from './product'

// Utility type which you can put in your utils file
type ID = Schema.Types.ObjectId

export interface IOrder {
    _id?: ID
    // Represents the relation between the order and the product
    productsIds: ID[]
    quantity: number
    // Optional type used when we want to populate the product in the order, will be defined as a virtual on the schema
    products?: IProduct[]
}

const orderSchema = new Schema<IOrder>({
    productsIds: [{ type: Schema.Types.ObjectId, ref: 'Product' }],
    quantity: Number
})

// Define the product field as a virtual for when we populate it for better usage

orderSchema.virtual('products', {
    ref: 'Product',
    localField: 'productID',
    foreignField: '_id',
})

export const Order = model<Iorder>('Order', orderSchema)