How do I use Mongoose aggregation in my Node.js application?

How do I use Mongoose aggregation in my Node.js application?

You can use Mongoose's aggregate method to perform aggregation operations on your MongoDB collections. Would you like a code example?

Yes, please provide a code example.

Sure! Here's a simple example:

const mongoose = require('mongoose');

const YourModel = mongoose.model('YourModel', yourSchema);

YourModel.aggregate([
  { $match: { status: 'active' } },
  { $group: { _id: '$category', total: { $sum: 1 } } }
]).exec((err, results) => {
  if (err) throw err;
  console.log(results);
});

This will group active documents by category and count them.

What other aggregation stages can I use?

You can use various stages like $match, $group, $sort, $project, and $lookup. Each serves a different purpose in data processing.