MongoDB get all documents with highest value in collection - mongodb

Question

Context:
I have a MongoDB full of Documents like this:
[
{
"_id": "615dc97907f597330c510279",
"code": "SDFSDFSDF",
"location": "ABC1",
"week_number": 39,
"year": 2020,
"region": "NA"
},
....
{
"_id": "615dc97907f597330c51027a",
"code": "SDFSGSGR",
"location": "ABC1",
"week_number": 42,
"year": 2021,
"region": "EU"
},
....
{
"_id": "615dc97607f597330c50ff50",
"code": "GGSFHSFS",
"location": "DEF2",
"week_number": 42,
"year": 2021,
"region": "EU",
"audit_result": {
"issues_found": true,
"comment": "comment."
}
}
]
Problem
I am trying to write an aggregation which should return all object with the highest "week_number" and highest "year". So with the example above, I want to return the full documents of _id "615dc97907f597330c51027a" and "615dc97607f597330c50ff50".
I tried multiple approaches. like first sorting and then grouping but with no success.
currently I have something like this, which seemed logical, but it returns all documents not only the one with the highest week and year
[
{
'$match': {
'$expr': {
'$max': '$week_number',
'$max': '$year'
}
}
}
]

Answer 1

You can do the followings in an aggregation pipeline:
$group by year and week_number; push the _id into an array for future lookup
$sort by year: -1 and week_number: -1
$limit to get the first grouping, which is the one with max year and week_number
$lookup the original documents using the previously stored array of _id in step 1
$replaceRoot to get back the documents
Here is the Mongo playground for your reference.