fix: check type before using string-only method (#2393)

* Update handlerUtils.ts

* Create .nvmrc

* Update handlerUtils.ts

* Update handlerUtils.ts

* maybe downgrade cli?

* chore: remove nvmrc

* Revert "maybe downgrade cli?"

This reverts commit 42d8ff9.

* chore: ?

* chore: how about different cli?

* chore: remove test debug code

Author: pieh

.github/workflows/test-integration.yml

@@ -28,7 +28,7 @@ jobs:
         with:
           deno-version: v1.x
       - name: Install netlify-cli and npm
-        run: npm install -g netlify-cli npm
+        run: npm install -g netlify-cli npm@10.2.4
       - name: NPM Install
         run: npm install
       - name: Run integration tests

packages/runtime/src/templates/handlerUtils.ts

@@ -135,10 +135,12 @@ export const augmentFsModule = ({
 
   // ...then monkey-patch it to see if it's requesting a CDN file
   promises.readFile = (async (file, options) => {
-    const baseUrl = getBase()
-
-    // We only care about page files
-    if (file.startsWith(pageRoot)) {
+    // file argument can be a string, URL, etc - Next.js cache reading uses a string
+    // and that's only thing we really want to handle here, so we just do type checking
+    // instead of trying to handle all possible type before checking weather read
+    // is about page files.
+    if (typeof file === 'string' && file.startsWith(pageRoot)) {
+      const baseUrl = getBase()
       // We only want the part after `.next/server/`
       const filePath = file.slice(pageRoot.length + 1)