Allow custom ID or properties on server functions

[techo207]

Hello, amazing framework! It's my favorite by far! ❤️

I would like to be able to add custom properties or metadata to a server function, similar to the existing url property.

My main use case is assigning a short, stable, unique identifier to each server function. I currently use .url for debugging and as a query key, but the generated URL can be quite long and isn't ideal for these purposes.

Something like this would be very useful:

export const findAddress = createServerFn({
metadata: (context: { url: string }) => ({
id: "MY_FN_" + shortHash(context.url),
}),
})
.validator(getInputSchema())
.handler(() => {})

Or, if a simpler static API is preferred:

export const findAddress = createServerFn({
id: "FIND_ADDRESS",
})
.validator(getInputSchema())
.handler(() => {})

Then the custom ID/properties could be accessed from the server function object:

findAddress.id

This would be useful for:

Debugging and logging server functions
Using short, stable identifiers as query keys
Tracing server function calls
Attaching application-specific metadata
Avoiding reliance on the generated .url as an identifier

The generated .url is still useful for routing/internal purposes, but having a dedicated custom identifier would make server functions much easier to identify and work with in application code.

Thanks for the amazing work on the framework!