[{"_id":1,"Data":{"a":{"levela":{"fname":"fname"},"levelfacility":[]}}},{"_id":2,"Data":{"a":{"levela":{},"levelfacility":[{"facility":"facility"}]}}},{"_id":3,"Data":{"a":{"levela":{},"levelfacility":[]}}}]

db.collection.aggregate([{"$addFields":{"Data.a.levela":{"$cond":{"if":{$ne:[{"$ifNull":["$Data.a.levela.fname",null]},null]},"then":{"fname":"$Data.a.levela.fname","fnameNORM":{"$toUpper":"$Data.a.levela.fname"}},"else":"$Data.a.levela"}}}},{"$addFields":{"Data.a.levelfacility":{"$map":{"input":"$Data.a.levelfacility","as":"lf","in":{"$cond":{"if":{$ne:[{"$ifNull":["$$lf.facility",null]},null]},"then":{"facility":"$$lf.facility","facilityNORM":{"$toUpper":"$$lf.facility"}},"else":"$$lf"}}}}}}])