From 15f30e73509fda68e0ae9a1f7d388d0046cb3b62 Mon Sep 17 00:00:00 2001
From: Alan Agius <17563226+alan-agius4@users.noreply.github.com>
Date: Mon, 10 Nov 2025 08:42:46 +0000
Subject: [PATCH] =?UTF-8?q?fix(@angular/ssr):=20handle=20undefined=20`?=
 =?UTF-8?q?=C9=B5getOrCreateAngularServerApp`?=
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This change fixes 'Error: ɵgetOrCreateAngularServerApp is not a function' which can occur when the dev server stops updating if the user saves while the HTML is in an invalid state.

Closes #31671
---
 packages/angular/ssr/src/app-engine.ts | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/packages/angular/ssr/src/app-engine.ts b/packages/angular/ssr/src/app-engine.ts
index dd204a4b595f..12919de67ba4 100644
--- a/packages/angular/ssr/src/app-engine.ts
+++ b/packages/angular/ssr/src/app-engine.ts
@@ -142,12 +142,17 @@ export class AngularAppEngine {
       return null;
     }
 
+    const { ɵgetOrCreateAngularServerApp } = entryPoint;
+    if (!ɵgetOrCreateAngularServerApp) {
+      // Sometimes in Vite `ɵgetOrCreateAngularServerApp` is undefined,
+      // which causes a runtime error `Error: ɵgetOrCreateAngularServerApp is not a function`
+      // See: https://github.com/angular/angular-cli/issues/31671
+      return null;
+    }
+
     // Note: Using `instanceof` is not feasible here because `AngularServerApp` will
     // be located in separate bundles, making `instanceof` checks unreliable.
-    const ɵgetOrCreateAngularServerApp =
-      entryPoint.ɵgetOrCreateAngularServerApp as typeof getOrCreateAngularServerApp;
-
-    const serverApp = ɵgetOrCreateAngularServerApp({
+    const serverApp = (ɵgetOrCreateAngularServerApp as typeof getOrCreateAngularServerApp)({
       allowStaticRouteRender: AngularAppEngine.ɵallowStaticRouteRender,
       hooks: AngularAppEngine.ɵhooks,
     });