Database
[{"_id":ObjectId("0123456789abcdf012345678"),"date":[ISODate("2022-05-27T00:00:00.000+00:00"),ISODate("2022-05-28T00:00:00.000+00:00"),ISODate("2022-05-29T00:00:00.000+00:00"),ISODate("2022-05-30T00:00:00.000+00:00"),ISODate("2022-05-31T00:00:00.000+00:00"),ISODate("2022-06-01T00:00:00.000+00:00"),ISODate("2022-06-02T00:00:00.000+00:00"),]}]
Query
db.collection.aggregate([{"$replaceWith":{"$mergeObjects":[{"_id":"$_id"},{"$arrayToObject":{"$map":{"input":{"$range":[0,{"$size":"$date"}]},"as":"dateNum","in":{"k":{"$concat":["date",{"$toString":{"$add":["$$dateNum",1]}}]},"v":{"$arrayElemAt":["$date","$$dateNum"]}}}}}]}}])