From 24f809cbe957e954fa8c7f1d768d4a514aea3bc5 Mon Sep 17 00:00:00 2001
From: Richard J <106497642+richard-stafflink@users.noreply.github.com>
Date: Fri, 11 Jul 2025 00:04:34 +0000
Subject: [PATCH] fix(api-server): lambdaLoader: improve handler import
 logic...

For ESModule and CommonJS compatibility.
When using a bundler like Rollup, the handler function is exported as default.
---
 .../api-server/src/plugins/lambdaLoader.ts     | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/packages/api-server/src/plugins/lambdaLoader.ts b/packages/api-server/src/plugins/lambdaLoader.ts
index a554dab536ab..2233e2e39355 100644
--- a/packages/api-server/src/plugins/lambdaLoader.ts
+++ b/packages/api-server/src/plugins/lambdaLoader.ts
@@ -28,7 +28,23 @@ export const setLambdaFunctions = async (foundFunctions: string[]) => {
     const ts = Date.now()
     const routeName = path.basename(fnPath).replace('.js', '')
 
-    const { handler } = await import(`file://${fnPath}`)
+    const fnImport = await import(`file://${fnPath}`)
+    const handler: Handler = (() => {
+      if ('handler' in fnImport) {
+        // ESModule export of handler - when using `export const handler = ...` - most common case
+        return fnImport.handler
+      }
+      if ('default' in fnImport) {
+        if ('handler' in fnImport.default) {
+          // CommonJS export of handler - when using `module.exports.handler = ...` or `export default { handler: ... }`
+          // This is less common, but required for bundling tools that export a default object, like esbuild or rollup
+          return fnImport.default.handler
+        }
+        // Default export is not expected, so skip it
+      }
+      // If no handler is found, return undefined - we do not want to throw an error
+    })()
+
     LAMBDA_FUNCTIONS[routeName] = handler
     if (!handler) {
       console.warn(