Mongoose and how to group by count

It may be an unpopular opinion but I don't like Mongoosejs docs - I think they take a lot of knowledge for granted and their code samples are poor. But maybe it's me :shrugs:

Anyway, I have a collection of documents that looks like:

[ { _id: 1, category: food, name: avocado }, { _id: 2, category: food, name: orange }, { _id: 3, category: drink, name: milk }, ] 

I wanted to create an endpoint that returns data like:
g

data: { food: 2, drink: 1 } 

Basically the name of the category and the count of documents. Well, that brought me on a journey that span a couple of tutorials and some other SO thread.

Disclaimer: I should probably be more familiar with MongoDB. I used to be, but like many things in life, you forget them and I am not ready to ramp up with MongoDB again and also with Mongoose, again. I just went straight to Mongoose.

First, I discovered grouping with Mongoose is called Aggregate. I found Model.aggregate(), which brought me to this tutorial. Their The $group Stage section gave me a solution that worked for me:

const data = await YourModelName.aggregate([ { $group: { _id: '$category', count: { $sum: 1 } // this means that the count will increment by 1 } } ]); 

But data was returned slightly different, not a big deal:

data: [ { _id: "food", count: 2 }, { _id: "drink", count: 1 } ] 

Not a big deal and probably as good as it gets, but I continued exploring. This brought me to a number of SO threads (there were not that many), slightly different topic but it revolved to more or less the same syntax.

And then, by chance, I discovered aggregate.sortByCount() here, which does the same out of the box!

const data = await Machine.aggregate().sortByCount("category"); 

sortByCount expects the name of the field and it does the whole $group, $count, etc for you. Or at least this is what happened for me. Much more straightforward.

I think this is good enough for me for now, I will stop exploring this topic, hope this was useful for you (: