zodToJsonSchema: pipeStrategy 'output'

[testerez]

Using transform in the output zod schema works pretty well.
Unfortunately, the generated openapi document indicates the wrong type in response.

Here is what I get:

"amount": {
  "type": "integer",
  "format": "int64"
}

I've found that we could get the correct response definition by using zod pipe and pipeStrategy 'output':

.output(z.object({ amount: z
    .bigint()
    .transform((v) => v.toString())
    .pipe(z.string().regex(/^\d+$/)) }))

Then I get the right response definition:

"amount": {
  "type": "string",
  "pattern": "^\\d+$"
}

Related issue: #264

[testerez]

Hey @jlalmes, any chance to have this merged?

[StefanTerdell]

I'm working on another option that would be useful for this case (callback). Maybe you could find a way to expose the zodToJsonSchema options object through the trpc-openapi API? BigInt serialization isn't really standardized with JSON after all, so a one-size-fits-all solution is unlikely

[testerez]

Thanks for looking that this PR @StefanTerdell ,
The solution I'm proposing here is not specific to BigInt. It enables usage of z.pipe for any use case. And I think it's the correct way to generate the openapi schema. What the API returns is the output of the zod schema, not the input.