Querying subscription documents that match object

Question

I have subscriptions collection in the database, e.g:

[{
  _id: new ObjectId(...),
  query: {
    size: { $in: [1, 2, 3] }
  }
}, {
  _id: new ObjectId(...),
  query: {
    name: { $eq: 'Shirt' },
  }
}]

I need to find all subscriptions whose query matches the object. Is it possible? E.g:

Subscriptions.aggregate([{
  $reverseMatch: {
    size: 1,
    name: 'Shirt',
  },
}]);

Answer 1

Subscriptions.aggregate([
  {
    $match: {
      $nor: [
        { "query.size": 1 }, // Exclude documents where size is 1
        { "query.size": 2 }, // Exclude documents where size is 2
        { "query.size": 3 }  // Exclude documents where size is 3
      ]
    }
  }
]);

This query effectively filters out subscriptions where the size field inside the query object matches any of the specified values (1, 2, or 3), thereby giving us the subscriptions that do not match the specified object. It's a neat way to handle such filtering requirements in MongoDB aggregation pipelines.