Database
[{"date":ISODate("2020-01-16T08:54:17.604Z"),"dateS":"2020-01-16T08"}]
Query
db.collection.aggregate([{$project:{outputDate:{$dateFromParts:{"year":{$year:"$date"},"month":{$month:"$date"},"day":{$dayOfMonth:"$date"},"hour":{$hour:"$date"}}}}}])