fix(routing): use serializeHandlerFn for routed middleware

src/build/virtual/routing.ts

@@ -48,7 +48,7 @@ ${allHandlers
 
 export const findRoute = ${nitro.routing.routes.compileToString({ serialize: (h) => serializeHandler(h, { tracing: traceH3 }) })}
 
-export const findRoutedMiddleware = ${nitro.routing.routedMiddleware.compileToString({ serialize: serializeHandler, matchAll: true })};
+export const findRoutedMiddleware = ${nitro.routing.routedMiddleware.compileToString({ serialize: serializeHandlerFn, matchAll: true })};
 
 export const globalMiddleware = [
   ${nitro.routing.globalMiddleware.map((h) => (h.lazy ? h._importHash : `h3.toEventHandler(${h._importHash})`)).join(",")}

test/unit/virtual-routing.test.ts

@@ -52,4 +52,29 @@ describe("virtual/routing template", () => {
     expect(template).toContain(`import { wrapHandlerWithTracing } from "h3/tracing"`);
     expect(template).toContain("wrapHandlerWithTracing(h3.toEventHandler(_abc123))");
   });
+
+  it("serializes routed middleware with serializeHandlerFn instead of route record", () => {
+    const handler: NitroEventHandler & { _importHash: string } = {
+      route: "/api/**",
+      handler: "/path/to/middleware.ts",
+      _importHash: "_mid123",
+      middleware: true,
+    };
+    const nitroStub = {
+      options: { baseURL: "/", routeRules: {} },
+      routing: {
+        routes: { routes: [], compileToString: () => "{}" },
+        routedMiddleware: {
+          routes: [{ route: "/api/**", data: handler }],
+          compileToString: ({ serialize }: { serialize: (h: unknown) => string }) =>
+            `{"/api/**":${serialize(handler)}}`,
+        },
+        globalMiddleware: [],
+      },
+    } as unknown as Nitro;
+    const template = routing(nitroStub).template();
+    expect(template).toContain(
+      'export const findRoutedMiddleware = {"/api/**":h3.toEventHandler(_mid123)};'
+    );
+  });
 });