How to send Dates and Regexes between Server and Client

[Overdash]

I recently ripped out tRPC to use oRPC on a NextJS project. Whenever I call a procedure with a date input it fails (dates as Outputs succeed). Here's a contrived example:

export const healthCheck = publicProcedure
  .route({ method: "POST" })
  .input(z.object({ text: z.string(), date: z.coerce.date() }))
  .handler(async ({ input, context: ctx }) => {
    ctx.logger.info(input.date.getUTCDay(), "Saying hello...")

    return {
      greeting: `Hello ${input.text}`,
      date: new Date(),
    }
  })

// ... stub

const { data } = useSuspenseQuery(
    orpc.healthCheck.queryOptions({
      input: { text: "Testing", date: new Date() },  // FIXME: The date fails
    })
  )

The component renders infinitely and we get validation errors on the backend. The docs say that Dates are supported - what am I doing wrong?

[unnoq]

Show me your RPCLink and RPCClient setups

[Overdash]

Here's an example with the infinite render - sometimes it raises the validation error, but it's not deterministic; unsure why.

NB: also tried to memoize the date: const date = useMemo(() => new Date(), []);
No dice...

Perhaps is a weird interaction with react query? (Haven't had time to investigate this far)

[unnoq]

I just tried your playground. useSuspenseInfiniteQuery triggered an infinite loop, so I switched to useInfiniteQuery, and it worked as expected.

[Overdash]

I think this is an SSR/Hydration issue. It does work with non Suspense hooks, but only because those hooks don't wait on the server. If I introduce some artificial delay, useInfiniteQuery and useQuery start to loop again. If I use a constant date e.g. new Date(2025, 5, 23), it stops looping.

The validation is not the issue, but the interaction between suspenseful hooks + next.js is.

That said, tRPC has a HydrateClient to play nice with server-components - why doesn't oRPC need one?.

Alternatively, this could be due to the changing date between the SSR re-render. Regardless, it's a pretty narrow edge-case, not sure if worth venturing deeper.

[Overdash]

Marking this as answered as I don't think it's oRPC problem.
Could be hydration related but not worth the energy to dive deeper right now :)