$replaceRoot in mongodb aggregation

Question

I have a collection like this:

{
    \"_id\" : ObjectId(\"5bd1686ba64b9206349284db\"),
    \"type\" : \"Package\",
    \"codeInstances\" : [ 
        {
                  


        

Answer 1

You can try below aggregation using $replaceRoot

db.collection.aggregate([
  { "$match": { "codeInstances.name": "b", "type": "Package" }},
  { "$unwind": "$codeInstances" },
  { "$match": { "codeInstances.name": "b", "type": "Package" }},
  { "$replaceRoot": { "newRoot": "$codeInstances" }}
])