Pass OPTIONS through Vite CORS to handler (#157)

Co-authored-by: ask-bonk[bot] <ask-bonk[bot]@users.noreply.github.com>
Co-authored-by: southpolesteve <[email protected]>
Co-authored-by: Steve Faulkner <[email protected]>

Author: ask-bonk[bot]

packages/vinext/src/index.ts

@@ -1275,6 +1275,11 @@ hydrate();
         const viteConfig: Record<string, any> = {
           // Disable Vite's default HTML serving - we handle all routing
           appType: "custom",
+          // Let OPTIONS requests pass through Vite's CORS middleware to our
+          // route handlers so they can set the Allow header and run user-defined
+          // OPTIONS handlers. Without this, Vite's CORS middleware responds to
+          // OPTIONS with a 204 before the request reaches vinext's handler.
+          server: { cors: { preflightContinue: true } },
           // Externalize React packages from SSR transform — they are CJS and
           // must be loaded natively by Node, not through Vite's ESM evaluator.
           // Skip when targeting Cloudflare Workers (they bundle everything).

tests/e2e/app-router/api-routes.spec.ts

@@ -217,11 +217,6 @@ test.describe("Route Handler HTTP Methods (OpenNext compat)", () => {
 
   test("OPTIONS returns 204 with Allow header", async ({ request }) => {
     // Ref: opennextjs-cloudflare methods.test.ts "OPTIONS"
-    // Note: vinext auto-generates OPTIONS responses based on exported methods,
-    // so our explicit OPTIONS handler may or may not be called depending on
-    // whether vinext intercepts before reaching the handler.
-    // KNOWN GAP: vinext's auto-OPTIONS does not set the Allow header yet.
-    test.fixme(true, "vinext auto-OPTIONS does not set Allow header — feature gap");
     const res = await request.fetch(`${BASE}/api/methods`, {
       method: "OPTIONS",
     });