Start: createServerFn cannot return null

[SeanCassiere]

Which project does this relate to?

Router

Describe the bug

All details are found in this discussion thread on Discord - https://discord.com/channels/719702312431386674/1306957125246914590

The crust of the matter is that you aren't able to return null from a createServerFn call.

const fn = createServerFn().handler(async () => {
    return null
})

await fn(); // undefined

Your Example Website or App

https://discord.com/channels/719702312431386674/1306957125246914590

Steps to Reproduce the Bug or Issue

Create a server function returning null and see that at runtime it does not return the value, instead, it returns undefined.

Expected behavior

The returned null value from the server function should correctly get piped down to the caller.

Screenshots or Videos

No response

Platform

N/A

Additional context

No response

[SeanCassiere]

Need to investigate the issue.

The issue/bug has been investigated and a reproduction has been created.