fix(@angular/ssr): adopt bootstrapServerApplication for streamlined server bootstrap

This commit updates the SSR implementation to use the new `bootstrapServerApplication` function. This simplifies the server-side rendering (SSR) bootstrap process for standalone applications by making it more explicit and removing the need for a custom `main.server.ts` file that wraps `bootstrapApplication`.

Key changes:
- The SSR engine is updated to leverage the new bootstrap function.
- The `ng add @angular/ssr` schematic is updated to generate code using `bootstrapServerApplication`.
- Internal utilities and tests are updated to align with this new approach.

Author: alan-agius4

packages/angular/ssr/src/routes/ng-routes.ts

@@ -634,7 +634,7 @@ export async function getRoutesFromAngularRouterConfig(
       const moduleRef = await platformRef.bootstrapModule(bootstrap);
       applicationRef = moduleRef.injector.get(ApplicationRef);
     } else {
-      applicationRef = await bootstrap();
+      applicationRef = await bootstrap(platformRef.injector);
     }
 
     const injector = applicationRef.injector;

packages/angular/ssr/src/routes/route-config.ts

@@ -353,16 +353,16 @@ export function withAppShell(
  *
  * @example
  * Basic example of how you can enable server-side rendering in your application
- * when using the `bootstrapApplication` function:
+ * when using the `bootstrapServerApplication` function:
  *
  * ```ts
- * import { bootstrapApplication } from '@angular/platform-browser';
+ * import { bootstrapServerApplication } from '@angular/platform-server';
  * import { provideServerRendering, withRoutes, withAppShell } from '@angular/ssr';
  * import { AppComponent } from './app/app.component';
  * import { SERVER_ROUTES } from './app/app.server.routes';
  * import { AppShellComponent } from './app/app-shell.component';
  *
- * bootstrapApplication(AppComponent, {
+ * bootstrapServerApplication(AppComponent, {
  *   providers: [
  *      provideServerRendering(
  *         withRoutes(SERVER_ROUTES),

packages/angular/ssr/src/utils/ng.ts

@@ -17,6 +17,7 @@ import {
 import {
   INITIAL_CONFIG,
   ɵSERVER_CONTEXT as SERVER_CONTEXT,
+  bootstrapServerApplication,
   platformServer,
   ɵrenderInternal as renderInternal,
 } from '@angular/platform-server';
@@ -31,7 +32,7 @@ import { joinUrlParts, stripIndexHtmlFromURL } from './url';
  * - A reference to an Angular component or module (`Type<unknown>`) that serves as the root of the application.
  * - A function that returns a `Promise<ApplicationRef>`, which resolves with the root application reference.
  */
-export type AngularBootstrap = Type<unknown> | (() => Promise<ApplicationRef>);
+export type AngularBootstrap = Type<unknown> | ReturnType<typeof bootstrapServerApplication>;
 
 /**
  * Renders an Angular application or module to an HTML string.
@@ -90,7 +91,7 @@ export async function renderAngular(
       const moduleRef = await platformRef.bootstrapModule(bootstrap);
       applicationRef = moduleRef.injector.get(ApplicationRef);
     } else {
-      applicationRef = await bootstrap();
+      applicationRef = await bootstrap(platformRef.injector);
     }
 
     // Block until application is stable.

packages/angular/ssr/test/BUILD.bazel

@@ -12,7 +12,7 @@ ts_project(
         "//:node_modules/@angular/common",
         "//:node_modules/@angular/compiler",
         "//:node_modules/@angular/core",
-        "//:node_modules/@angular/platform-browser",
+        "//:node_modules/@angular/platform-server",
         "//:node_modules/@angular/router",
         "//:node_modules/@types/node",
         "//packages/angular/ssr",

packages/angular/ssr/test/testing-utils.ts

@@ -13,7 +13,7 @@ import {
   Type,
   provideZonelessChangeDetection,
 } from '@angular/core';
-import { bootstrapApplication } from '@angular/platform-browser';
+import { bootstrapServerApplication } from '@angular/platform-server';
 import { RouterOutlet, Routes, provideRouter } from '@angular/router';
 import { destroyAngularServerApp } from '../src/app';
 import { ServerAsset, setAngularAppManifest } from '../src/manifest';
@@ -90,8 +90,8 @@ export function setAngularAppTestingManifest(
       `,
       },
     },
-    bootstrap: async () => () => {
-      return bootstrapApplication(rootComponent, {
+    bootstrap: async () => {
+      return bootstrapServerApplication(rootComponent, {
         providers: [
           provideZonelessChangeDetection(),
           provideRouter(routes),

packages/schematics/angular/server/files/application-builder/standalone-src/main.server.ts.template

@@ -1,7 +1,5 @@
-import { bootstrapApplication } from '@angular/platform-browser';
+import { bootstrapServerApplication } from '@angular/platform-server';
 import { <%= appComponentName %> } from '<%= appComponentPath %>';
 import { config } from './app/app.config.server';
 
-const bootstrap = () => bootstrapApplication(<%= appComponentName %>, config);
-
-export default bootstrap;
+export default bootstrapServerApplication(<%= appComponentName %>, config);

packages/schematics/angular/server/files/server-builder/standalone-src/main.server.ts.template

@@ -1,7 +1,5 @@
-import { bootstrapApplication } from '@angular/platform-browser';
+import { bootstrapServerApplication } from '@angular/platform-server';
 import { <%= appComponentName %> } from '<%= appComponentPath %>';
 import { config } from './app/app.config.server';
 
-const bootstrap = () => bootstrapApplication(<%= appComponentName %>, config);
-
-export default bootstrap;
+export default bootstrapServerApplication(<%= appComponentName %>, config);

packages/schematics/angular/utility/standalone/util.ts

@@ -55,14 +55,12 @@ export function getSourceFile(tree: Tree, path: string): ts.SourceFile {
   return source;
 }
 
-/** Finds the call to `bootstrapApplication` within a file. */
+/** Finds the call to `bootstrapApplication` or `bootstrapServerApplication` within a file. */
 export function findBootstrapApplicationCall(tree: Tree, mainFilePath: string): ts.CallExpression {
   const sourceFile = getSourceFile(tree, mainFilePath);
-  const localName = findImportLocalName(
-    sourceFile,
-    'bootstrapApplication',
-    '@angular/platform-browser',
-  );
+  const localName =
+    findImportLocalName(sourceFile, 'bootstrapApplication', '@angular/platform-browser') ??
+    findImportLocalName(sourceFile, 'bootstrapServerApplication', '@angular/platform-server');
 
   if (localName) {
     let result: ts.CallExpression | null = null;
@@ -86,7 +84,9 @@ export function findBootstrapApplicationCall(tree: Tree, mainFilePath: string):
     }
   }
 
-  throw new SchematicsException(`Could not find bootstrapApplication call in ${mainFilePath}`);
+  throw new SchematicsException(
+    `Could not find bootstrapApplication or bootstrapServerApplication call in ${mainFilePath}`,
+  );
 }
 
 /**