fix server-fns client runtime

Author: lxsmnsyc

packages/start/src/fns/client.ts

@@ -193,12 +193,7 @@ async function fetchServerFunction(
   return result;
 }
 
-export function createServerReference(id: string) {
-  let baseURL = import.meta.env.BASE_URL ?? "/";
-  if (!baseURL.endsWith("/")) baseURL += "/";
-
-  const fn = (...args: any[]) => fetchServerFunction(`${baseURL}_server`, id, {}, args);
-
+function enhanceServerFunction(id: string, baseURL: string, fn: Function) {
   return new Proxy(fn, {
     get(target, prop, receiver) {
       if (prop === "url") {
@@ -235,6 +230,27 @@ export function createServerReference(id: string) {
   });
 }
 
+export function createServerReference(id: string) {
+  let baseURL = import.meta.env.BASE_URL ?? "/";
+  if (!baseURL.endsWith("/")) baseURL += "/";
+
+  const fn = (...args: any[]) => fetchServerFunction(`${baseURL}_server`, id, {}, args);
+  return enhanceServerFunction(id, baseURL, fn);
+}
+
+export function createServerFunction<T extends any[], R>(
+  id: string,
+  fn: () => Promise<(...args: T) => Promise<R>>,
+) {
+  let baseURL = import.meta.env.BASE_URL ?? "/";
+  if (!baseURL.endsWith("/")) baseURL += "/";
+  let instance: (...args: T) => Promise<R>;
+  return enhanceServerFunction(id, baseURL, async (...args: T) => {
+    instance = instance || (await fn());
+    return instance(...args);
+  });
+}
+
 export function createClientReference(Component: Component<any>, id: string) {
   return Component;
 }