Database
[{"_id":ObjectId("5b7e55bb0f81ba2c5b0b54c8"),"userId":16,"userListId":ObjectId("5b7e85f956de7e6ead026e23"),"createdAt":1535006139565.0},{"_id":ObjectId("5b7e55bb0f81ba2c5b0b54a9"),"userId":16,"userListId":ObjectId("5b7e85f956de7e6ead026e23"),"createdAt":1535006139564.0},{"_id":ObjectId("5b7e55bb0f81ba2c5b0b54b4"),"userId":16,"userListId":ObjectId("5b7e85f956de7e6ead026e23"),"createdAt":1535006139565.0},{"_id":ObjectId("5b7e55bb0f81ba2c5b0b54c4"),"userId":16,"userListId":ObjectId("5b7e85f956de7e6ead026e23"),"createdAt":1535006139565.0}]
Query
db.collection.aggregate([{$match:{userId:16,userListId:ObjectId("5b7e85f956de7e6ead026e23"),}},{$sort:{"createdAt":1}},{$group:{_id:"$domain","websites":{$push:{"_id":"$_id","userId":"$userId","userListId":"$userListId","createdAt":"$createdAt"}}}}])