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Discussion on: Custom validation with database in NestJS

smolinari profile image
Scott Molinari • Edited

Ok. Looked again at the code. My bad on the message. I was thinking in terms of creation of the user (and the user being unique), whereas the code is talking about the retrieval of the user. :) What I was thinking as a validation would be on a create or update DTO.

I see what you are saying with testing, however, that's also the point I'm trying to make to some degree I believe. Unit tests should test that the validation system works, but the conditions of the validation are meta to the "unit". The conditions are and must be variable as business changes all the time and thus, those rules themselve don't need testing. The system/ unit should take a set of rules and run validation on that set of rules. What's in the rules doesn't matter, the proper validation does.

The "testing" of the rules would lie solely with the business, since they are setting them. And because the rules are metadata to the system, it has to be purely manual on their part. Or, it could be within integration testing, but that would also be insanely complex, depending on the validations needed. :D

The goal I'm shooting for is to have a system of validation (and authorization) that is mainly independent of the programmer. It would be designed for a larger system with complex business operations. I've seen it done from a user's perspective. I'm just not quite sure how to make it happen with Nest. But, your article gave me more insight into the topic. Thanks!

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avantar profile image
Krzysztof Szala Author • Edited

It's interesting point of view Scott, but I'll stand by my opinion, that validation rules belong to the code base, not to the storage ;) Anyway, thanks for great comments, appriciate that! Have a nice weekend!