Query MongoDB w/Mongoose on an Array of objects - node.js

Question

I am having a rough time querying my collection of data, Im building a simple E-Comm platform and in that platform i want to be able to have categories for the products. the idea is simple, each category should be its own object in the database that has a collection of products, however each product can have multiple categories, this is for products that might fit into one or more category definitions.
here is the model for the categories
import mongoose from "mongoose";
const categorySchema = mongoose.Schema(
{
cat_name: {
type: String,
required: true,
unique: true,
},
cat_items: [
{
product: {
type: mongoose.Schema.Types.ObjectId,
ref: "Product",
},
},
],
// Adds a relationship between a User admin and a product
// this is useful to see which admin, if multiple created a category
user: {
type: mongoose.Schema.Types.ObjectId,
required: true,
ref: "User",
},
},
{ timestamps: true }
);
const Category = mongoose.model("Category", categorySchema);
export default Category;
Here is the Product model
const productSchema = mongoose.Schema(
{
// Adds a relationship between a User admin and a product
user: {
type: mongoose.Schema.Types.ObjectId,
required: true,
ref: "User",
},
name: {
type: String,
required: true,
},
image: {
type: String,
required: true,
},
brand: {
type: String,
required: true,
},
category: {
type: String,
required: true,
},
categories: [
{
category: {
type: mongoose.Schema.Types.ObjectId,
ref: "Category",
},
},
],
description: {
type: String,
required: true,
},
reviews: [reviewSchema],
rating: {
type: Number,
required: true,
default: 0,
},
numReviews: {
type: Number,
required: true,
default: 0,
},
price: {
type: Number,
required: true,
default: 0,
},
countInStock: {
type: Number,
required: true,
default: 0,
},
},
{
timestamps: true,
}
);
const Product = mongoose.model("Product", productSchema);
export default Product;
I believe the overall problem is the way i have the models setup, because any query i run on the categories object to return the products associated with it in cat_items, does not return any products it simply returns an empty array.
here is the simple function to return data
const products = await category.map((product)=> { return Product.findById(product._id)})
here im pulling out the array of category items, and mapping over them looking for the product in the database by the _id which is what product is example: 620e626203a59f0004e5a8c6 this in theory if you had 3 items, would return a new array of the product objects that i can send to the client, however every attempt only returns a [] and im pretty sure this is all do in part to the way i have the models setup.
for reference this is what returning a category looks like in postman:
{
"category": {
"_id": "62102f5c2b990d0e7c7d9bf8",
"cat_name": "Pendants",
"user": "620af3311fe4c247904b84d9",
"cat_items": [
{
"_id": "620e626203a59f0004e5a8c6"
},
{
"_id": "620e626203a59f0004e5a8c6"
}
],
"createdAt": "2022-02-18T23:44:28.697Z",
"updatedAt": "2022-02-18T23:54:23.103Z",
"__v": 2
},
"products": [
{},
{}
]
}
where im trying to fill the products array with the actual products stashed in the database