[{_id:ObjectId("62307ccecabc9c2a2c4563e3"),username:"NEWUser",email:"user@mail.com",password:1234,level:1,domainArray:[{domainname:"example.com",domainvalue:4},{domainname:"facebook.com",domainvalue:3}]}]

db.collection.update({"username":"NEWUser"},{"$set":{"domainArray.$[].ouputArray":[]}})