MongoDB/Mongoose Query for multiple objects - node.js

Question

I got an MongoDB database that consists from 3 collections.
Categories
Subcategories
Products
Each product has the following model:
const ProductSchema = new Schema({
category: String,
subcategory: String,
name: String,
description: String,
price: String,
Image: [{
url: String,
filename: String
}],
deleteImages: []
});
What I want is to query a category then get the subcategories that belong to the category and (here is the question:) from the found subcategories query the products that belong to them.
app.get("/api/front/show/:category", asyncHandler(async(req,res)=>{
const category = req.params.category;
const subcategories = await SubCategoryMd.find({'category' : category});
const products = await ProductMd.find({/* Pass here the found subcategories */});
res.json({subcategories, products});
}));
How do I query multiple objects with find?

Answer 1

app.get("/api/front/show/:category", asyncHandler(async(req,res)=>{
let products = []
const category = req.params.category;
const subcategories = await SubCategoryMd.find({'category' : category});
const productsBulk = await ProductMd.find({}).collation({ locale: 'el' }).sort('name');
productsBulk.forEach(product => {
subcategories.forEach(subcategory => {
if(subcategory.name === product.subcategory){
products.push(product)
}
});
});
res.json({subcategories, products});
}));
This is a simple solution but it already pulls all the products and on top of that it is a very expensive function to run in my opinion.