Use of RawCreateParams for preprocess context

[ian-schu]

Hey there 👋🏻 I'm coming in from io-ts and very happy to have found this project.

TL;DR: assuming I've set up some of my own-built schemas correctly, I can't seem to get custom errors out of a preprocess-based schema.

---

What I have is an own-rolled schema like the following, based on the Dates example from your docs:

export const dateString = (
  params?: RawCreateParams // <-- added params
) =>
  z.preprocess(
    (input: unknown) => {
      if (!(typeof input == 'string')) {
        return;
      }

      const date = new Date(input);

      if (isNaN(date.getTime())) {
        return;
      }
      return date;
    },
    z.date(),
    params
  );

Pretty basic stuff. The idea is to use it like so:

const someSchema = z.object({
  updated_at: dateString({
    invalid_type_error: "Field `updated_at` had wrong type"
  })
})

Problem is whenever I do this, the custom error message doesn't seem to survive. I've tried all the fields under RawCreateParams, but still just get the default error object when parsing fails.

By contrast, doing this with a built-in schema works just fine:

const someSchema = z.object({
  someString: z.string({
    invalid_type_error: 'Custom error message here!',
  }),
});

So, what am I doing wrong? Or is this a bug with preprocess?

[ian-schu]

Possibly related to #696

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.