[__jonas]

Maybe I'm misunderstanding some aspect here, but it seems to me there are two choices for handling external data in TypeScript:

Either you parse / validate incoming data at an API boundary with a tool like zod, or you do not, and just trust that the data matches the exact shape you expect, opening yourself up to completely unexpected errors / behaviors if it does not.

The latter is probably a decent option if you fully control all components back to front, but if you really value type safety, the former seems like the way to go?

[cianuro_]

Yes, I agree. Some sort of check has to happen somewhere to validate the incoming payload. If you’re looking for type safety, it makes sense to use Zod for this.

To me it is bending the original tool (JS, async driven, weak typing) to fit a purpose it was not made for (hard typing, synchronous) in detriment of what it is that makes the tool good in the first place (IO performance).

[shepherdjerred]

This problem is not unique to JavaScript/TypeScript. You'll have this problem anytime you're working with unknown data.

Zod also works just fine async.