From 7d8ead31eb6a4d27d2d9b5766dc4c16cafcbbbbe Mon Sep 17 00:00:00 2001
From: Steve McNiven-Scott <steve@sitefinitysteve.com>
Date: Wed, 9 Sep 2026 19:59:08 -0400
Subject: [PATCH] fix(vite): replace the browser preload helper before esbuild
 minifies it

Fixes #11423
---
 .../helpers/dynamic-import-plugin.spec.ts     | 21 ++++++++++++++++++-
 .../vite/helpers/dynamic-import-plugin.ts     | 13 +++++++-----
 2 files changed, 28 insertions(+), 6 deletions(-)

diff --git a/packages/vite/helpers/dynamic-import-plugin.spec.ts b/packages/vite/helpers/dynamic-import-plugin.spec.ts
index cc3445c6ad..fc54821424 100644
--- a/packages/vite/helpers/dynamic-import-plugin.spec.ts
+++ b/packages/vite/helpers/dynamic-import-plugin.spec.ts
@@ -1,5 +1,5 @@
 import { describe, expect, it } from 'vitest';
-import { transformDynamicImports } from './dynamic-import-plugin.js';
+import { dynamicImportPlugin, transformDynamicImports } from './dynamic-import-plugin.js';
 
 const vitePreloadHelper = `const scriptRel = /* @__PURE__ */ (function detectScriptRel() {
   const relList = typeof document !== "undefined" && document.createElement("link").relList;
@@ -37,4 +37,23 @@ describe('dynamic import plugin', () => {
 		const source = 'export const value = 42;';
 		expect(transformDynamicImports(source)).toBe(source);
 	});
+
+	// Minified builds rename __vitePreload before generateBundle; the browser
+	// helper then survived and its window.dispatchEvent masked every dynamic
+	// import failure as "window is not defined".
+	it('replaces the helper in renderChunk as a post plugin, ahead of esbuild minification', () => {
+		const plugin = dynamicImportPlugin() as any;
+		expect(plugin.enforce).toBe('post');
+		expect(plugin.generateBundle).toBeUndefined();
+		const result = plugin.renderChunk(`${vitePreloadHelper}\nconst page = () => __vitePreload(() => import('./page.js'), []);`);
+		expect(result.code).not.toContain('document');
+		expect(result.code).toContain("import('~/page.js')");
+	});
+
+	it('returns null from renderChunk when nothing changes, including on already-transformed code', () => {
+		const plugin = dynamicImportPlugin() as any;
+		expect(plugin.renderChunk('export const value = 42;')).toBeNull();
+		const once = transformDynamicImports(`${vitePreloadHelper}\nexport const page = () => __vitePreload(() => import('./page.js'), []);`);
+		expect(plugin.renderChunk(once)).toBeNull();
+	});
 });
diff --git a/packages/vite/helpers/dynamic-import-plugin.ts b/packages/vite/helpers/dynamic-import-plugin.ts
index 9bdb1944ea..937edd569c 100644
--- a/packages/vite/helpers/dynamic-import-plugin.ts
+++ b/packages/vite/helpers/dynamic-import-plugin.ts
@@ -62,15 +62,18 @@ export function transformDynamicImports(code: string) {
 // Fix NativeScript dynamic imports by transforming paths and simplifying __vitePreload.
 // Vite still emits its browser preload helper when modulePreload is disabled:
 // https://github.com/vitejs/vite/issues/13952
+// Runs in renderChunk as a post plugin: user post plugins precede Vite's
+// esbuild minifier, so `__vitePreload` is still named when we look for it.
 export function dynamicImportPlugin() {
 	return {
 		name: 'nativescript-dynamic-import-fix',
-		generateBundle(_options, bundle) {
-			for (const chunk of Object.values(bundle) as any) {
-				if (chunk.type === 'chunk') {
-					chunk.code = transformDynamicImports(chunk.code);
-				}
+		enforce: 'post' as const,
+		renderChunk(code: string) {
+			const transformed = transformDynamicImports(code);
+			if (transformed === code) {
+				return null;
 			}
+			return { code: transformed, map: null };
 		},
 	};
 }