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Comment by CharlieDigital | Hacker News Reader

I recently went down this same rabbit hole for backend and stumbled on Typia[0] and Nestia[1] from the same developer. The DX with this is fantastic, especially when combined with Kysely[2] because now it's pure TypeScript end-to-end (no runtime schema artifacts and validations get AOT inlined).

I was so shocked by how good this is that I ended up writing up a small deck (haven't had time to write this into a doc yet): https://docs.google.com/presentation/d/1fToIKvR7dyvQS1AAtp4Y...

Shockingly good (for backend)

[0] Typia: https://typia.io/

[1] Nestia: https://nestia.io/

[2] https://kysely.dev/

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An interesting development with Typia is that it will need to be rewritten in Go to work with TypeScript 7. https://github.com/samchon/typia/issues/1534#issuecomment-27...

This is because it relies on patching the TypeScript implementation. I'm curious if its approach is even feasible with Go?

Between this and node adding the --experimental-strip-types option which would otherwise allow people to skip compilation, I'm not sure I would choose Typia right now. I'm sure it's a great library, but these don't bode well for its future.

I think it's fair to be skeptical, but I'm aligned with the overall approach the author took and I think the approach itself is what is interesting (pure TS + AOT).

Author + contributors and ts-patch team[0] seem up for a rewrite in Go based on that thread! Might be bumpy, but a pure TS approach is really appealing. I'm rooting for them :)

[0] https://github.com/nonara/ts-patch/issues/181#issuecomment-2...

I was going to ask about how pure types would fill the gap for other validations in Zod like number min/max ranges, but seeing the tags feature use intersection types for that is really neat. I tried assigning a `string & tags.MinLength<4>` to a `string & tags.MinLength<2>` and it's interesting that it threw an error saying they were incompatible.

That's because "minimum length" cannot be enforced in TypeScript. Maybe you already know this.

I'm not a Typia user myself, but my RPC framework has the same feature, and the MinLength issue you mentioned doesn't crop up if you only use the type tags at the client-server boundary, which is enough in my experience.

Thanks for sharing the deck! I had no idea Typia existed and it looks absolutely amazing. I guess I'll be trying it out this weekend or next :)

The docs have a bit of a rough edge because the author is Korean, but the examples are quite good and took me maybe 2-3 hours to work through.

Once everything clicked (quite shortly in), I was a bit blown away by everything "just working" as pure TypeScript; I can only describe the DX as "smooth" compared to Zod because now it's TypeScript.

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