How to check if that data already exist in the database during update (Mongoose And Express)

Question

How to do validations before saving the edited data in mongoose?

For example, if sample.name already exists in the database, the user will receive a som

Answer 1

If you're searching by an unique index, then using UserModel.count may actually be better for you than UserModel.findOne due to it returning the whole document (ie doing a read) instead of returning just an int.