Support Zod's "parseAsync" method

I’ve added an async transform to as Zod validator - and looks like tRPC does not support that.

Whan I use: z.string().nullable().transform(async (base64string) => { return await uploadToCloud(base64string).id; })

I get: “TRPCClientError: Asynchronous transform encountered during synchronous parse operation. Use .parseAsync instead.”

Any solution?

This is very important for situations like uploading files to external services.

Thanks!

[KATT]

Let me know if you need any further guidance on how to navigate the codebase when adding the parseAsync, @danielyogel. It should just be a matter of turning some functions async.

[danielyogel]

Do you mean that the input of the parsing can be different from the output? Does zod support inferring that?

No, this feature is already supported by Zod using “transform” / “transformAsync”. I mean, that the result of the validation (+ transform), can be “encoded” back into a different type that is still defined in the same schema. This can be used for example, for “encoding” back data that the tRPC’s resolver returns, using the same shema. Maybe io-ts explains this better than me: io-ts. Note that io-ts support this, but does not support async encoders/decoders 😦

I guess it is more related to Zod than tRPC for now - and I saw more people ask for this in Zod’s repo.