Database
[{"date1":ISODate("2019-05-20T19:04:35.000Z"),},{"date1":ISODate("2019-05-20T19:04:35.000Z"),"date2":ISODate("2019-05-20T19:04:35.000Z")},{"date3":ISODate("2019-05-20T19:04:35.000Z"),}]
Query
db.collection.aggregate([{$project:{date1:{$dateFromString:{dateString:{$dateToString:{format:"%Y-%m-%d",date:"$date1"}}}},date2:{$dateFromString:{dateString:{$dateToString:{format:"%Y-%m-%d",date:"$date2"}}}},date3:{$dateFromString:{dateString:{$dateToString:{format:"%Y-%m-%d",date:"$date3"}}}}}}])