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Server Function called from inside createClientOnlyFn results in error "Server function module export not resolved" #5381
Description
Which project does this relate to?
Start
Describe the bug
Calling a server function from inside a createClientOnlyFn triggers following error:
serverFnInfo {
functionName: 'serverFn_createServerFn_handler',
importer: [Function: importer]
}
fnModule [Object: null prototype] [Module] { component: [Getter] }
Error: Server function module export not resolved for serverFn ID: src_routes_index_tsx--serverFn_createServerFn_handler
export const Route = createFileRoute("/")({
component: Home,
});
const serverFn = createServerFn().handler(() => {
console.log("Hello");
});
const clientFn = createClientOnlyFn(() => {
serverFn();
});
function Home() {
return <button onClick={() => clientFn()}>Hello</button>;
}Your Example Website or App
https://github.com/ulrichstark/tanstack-start-server-fn-export-not-resolved
Steps to Reproduce the Bug or Issue
- Clone https://github.com/ulrichstark/tanstack-start-server-fn-export-not-resolved
- npm run dev
- click the button
Expected behavior
I expect to see "Hello" in terminal of server because I expect that I can call server functions from functions that are only available on the client.
Screenshots or Videos
No response
Platform
- Router / Start Version: 1.132.41
- OS: macOS
- Browser: Chrome
Additional context
Removing the wrapping createClientOnlyFn of clientFn fixes the issue.
Activity
schiller-manuel commentedon Oct 6, 2025
root cause here is order of compilation, we first apply
createClientOnlyFnwhich removes the reference toserverFnon the server and then dead code elimination kicks in.we need to rearrange the compiler plugins to make this work
manish-baghel commentedon Oct 12, 2025
@schiller-manuel
Is there any workaround for now?
In my case it was mainly happening due to tanstack-devtool vite plugin. Someone else also reported it TanStack/devtools#209
schiller-manuel commentedon Oct 12, 2025
@manish-baghel this is a different issue IMO, not related to this one here. are you using createClientOnlyFn?
fix: correct compiler plugin order, only handle createMiddlware in a …