From a5de7386588acd44791cb6ef8854c865709905f2 Mon Sep 17 00:00:00 2001
From: Kiko Beats <josefrancisco.verdu@gmail.com>
Date: Wed, 24 May 2023 13:30:00 +0100
Subject: [PATCH] add named export for Edge

---
 .../edge-functions/edge-handler-template.js   | 34 ++++++++++++++-----
 .../node/src/edge-functions/edge-handler.mts  |  9 ++---
 .../serverless-handler.mts                    |  4 +--
 3 files changed, 29 insertions(+), 18 deletions(-)

diff --git a/packages/node/src/edge-functions/edge-handler-template.js b/packages/node/src/edge-functions/edge-handler-template.js
index 33348e0ecf1..2b385869bc2 100644
--- a/packages/node/src/edge-functions/edge-handler-template.js
+++ b/packages/node/src/edge-functions/edge-handler-template.js
@@ -10,14 +10,14 @@ function getUrl(url, headers) {
   return urlObj.toString();
 }
 
-async function respond(userEdgeHandler, event, options, dependencies) {
+async function respond(handler, event, options, dependencies) {
   const { Request, Response } = dependencies;
   const { isMiddleware } = options;
   event.request.headers.set(
     'host',
     event.request.headers.get('x-forwarded-host')
   );
-  let response = await userEdgeHandler(
+  let response = await handler(
     new Request(
       getUrl(event.request.url, event.request.headers),
       event.request
@@ -62,15 +62,31 @@ async function parseRequestEvent(event) {
 
 // This will be invoked by logic using this template
 // eslint-disable-next-line @typescript-eslint/no-unused-vars
-function registerFetchListener(userEdgeHandler, options, dependencies) {
+function registerFetchListener(module, options, dependencies) {
   addEventListener('fetch', async event => {
+    let handler;
+    if (typeof module.default === 'function') {
+      handler = module.default;
+    } else {
+      if (
+        ['GET', 'HEAD', 'OPTIONS', 'POST', 'PUT', 'DELETE', 'PATCH'].some(
+          method => typeof module[method] === 'function'
+        )
+      ) {
+        const method = event.request.method ?? 'GET';
+        handler =
+          typeof module[method] === 'function'
+            ? module[method]
+            : () => new dependencies.Response(null, { status: 405 });
+      } else {
+        throw new Error(
+          'No default export was found. Add a default export to handle requests. Learn more: https://vercel.link/creating-edge-middleware'
+        );
+      }
+    }
+
     try {
-      const response = await respond(
-        userEdgeHandler,
-        event,
-        options,
-        dependencies
-      );
+      const response = await respond(handler, event, options, dependencies);
       return event.respondWith(response);
     } catch (error) {
       event.respondWith(toResponseError(error, dependencies.Response));
diff --git a/packages/node/src/edge-functions/edge-handler.mts b/packages/node/src/edge-functions/edge-handler.mts
index 2bcf431fead..afe873040c2 100644
--- a/packages/node/src/edge-functions/edge-handler.mts
+++ b/packages/node/src/edge-functions/edge-handler.mts
@@ -89,12 +89,7 @@ async function compileUserCode(
 
       // user code
       ${compiledFile.text};
-      const userEdgeHandler = module.exports.default;
-      if (!userEdgeHandler) {
-        throw new Error(
-          'No default export was found. Add a default export to handle requests. Learn more: https://vercel.link/creating-edge-middleware'
-        );
-      }
+      const handler = module.exports;
 
       // request metadata
       const isMiddleware = ${isMiddleware};
@@ -104,7 +99,7 @@ async function compileUserCode(
       ${edgeHandlerTemplate};
       const dependencies = { Request, Response };
       const options = { isMiddleware, entrypointLabel };
-      registerFetchListener(userEdgeHandler, options, dependencies);
+      registerFetchListener(handler, options, dependencies);
     `;
 
     return {
diff --git a/packages/node/src/serverless-functions/serverless-handler.mts b/packages/node/src/serverless-functions/serverless-handler.mts
index 3f545cefe6e..e31f384f5e7 100644
--- a/packages/node/src/serverless-functions/serverless-handler.mts
+++ b/packages/node/src/serverless-functions/serverless-handler.mts
@@ -21,7 +21,7 @@ type ServerlessFunctionSignature = (
   res: ServerResponse | VercelResponse
 ) => void;
 
-const [nodeMajor] = process.versions.node.split('.').map(v => Number(v));
+const [NODE_MAJOR] = process.versions.node.split('.').map(v => Number(v));
 
 /* https://nextjs.org/docs/app/building-your-application/routing/router-handlers#supported-http-methods */
 const HTTP_METHODS = [
@@ -57,7 +57,7 @@ async function compileUserCode(
   }
 
   if (HTTP_METHODS.some(method => typeof listener[method] === 'function')) {
-    if (nodeMajor < 18) throw new Error('Node.js v18 or above is needed')
+    if (NODE_MAJOR < 18) throw new Error('Node.js v18 or above is needed');
     const { getWebExportsHandler } = await import('./helpers-web.js');
     return getWebExportsHandler(listener, HTTP_METHODS);
   }