Database
[{"_id":"61cea071cfa3c96b9a4d2657","name":"Utils","children":[{"name":"Code","_id":"61cebb4e6c4a5c643494d1a1","children":[{name:"jahn"}]},{"name":"Image","_id":"61ceb8ad6c4a5c643494d11e","children":[]}]},{"_id":"61cea071cfa3c96b9a4d2111","name":"Names","children":[{"name":"que","_id":"61cebb4e6c4a5c643494d1a1","children":[]},{"name":"filter","_id":"61cebb4e6c4a5c643494d1a1","children":[{name:"jahn"}]}]},]
Query
db.collection.aggregate([{$project:{_id:1,name:1,children:{"$filter":{"input":"$children","cond":{"$ne":["$$this.children",[]]}}}}}])