Mongoose, Sort Results by Reference Attributes - node.js

Question

I will attempt to address the problem as clearly as possible.
Let's say I have two collections, Col_A and Col_B.
Col_A has an attribute, attribute C, that references our other collection, Col_B, via ObjectID.
image for visual reference
I want to query for documents from Col_A and sort by attribute E in Col_B.
A practical example, if the above is too broad, would be Users and Listings on a site like eBay. For this example, let's say Col_A is "Listings", Col_B is "Users", attribute C is "seller", and attribute E is "rating".
Query: grab all listings matching some criteria, sorted by sellers with the highest rating
That would mean "grab all documents from Listings matching some given criteria, and sort the results by the rating attribute for each Users document the listings reference.
How would one go about doing this? I understand how to apply basic sorting logic via mongoose, such as:
Listings.find({"attribute A" : "something"}).sort({"some_field": "uhh"}).exec(function(err, docs) { ... });
, but can I nest in the attributes for referenced documents and sort by those? Do I need to somehow apply queries within the sort parameters or something? Is Mongoose capable of something like this? I looked at Mongoose's populate functionality, but I can't get anything working, and apparently there's a bug that discourages folks from actually using populated documents for sorting.
Github Issue
I apologize if this question has been answered already. I've been digging through the documentation, SO, and various other sites, but I can't get anything going. Thanks in advance!

Answer 1

You could use populate method to populate seller and the query would return an array like this:
[
{
title: 'Listing #1',
seller: {
name: 'John',
rating: 100
}
}
{
title: 'Listing #2',
seller: {
name: 'John',
rating: 20
}
}
]
then you can sort the data like this:
Listings.find({"attribute A" : "something"}).populate('seller').exec(function(err, docs) {
docs.sort(function compare(a, b){
let c = 0;
if (a.seller.rating > b.seller.rating) {
c = 1;
} else if (b.seller.rating > a.seller.rating) {
c = -1;
}
return c;
});
// return or response with docs
});
It might not be what you are looking but I tried :)
Mongo or Mongoose will not do this kind of sort since populate method makes 2 queries and Mongo doesn't know there's any relation between them.