fix(@angular/ssr): accurately calculate content length for static pages with \r\n

JS engines convert `\r\n` to `\n` in template literals, potentially leading to incorrect byte length calculations. This fix ensures the correct content length is determined.

Closes angular#29567

Author: alan-agius4

packages/angular/build/src/utils/server-rendering/manifest.ts

@@ -8,6 +8,7 @@
 
 import type { Metafile } from 'esbuild';
 import { extname } from 'node:path';
+import { type Context, createContext, runInContext } from 'node:vm';
 import { NormalizedApplicationBuildOptions } from '../../builders/application/options';
 import { type BuildOutputFile, BuildOutputFileType } from '../../tools/esbuild/bundler-context';
 import { createOutputFile } from '../../tools/esbuild/utils';
@@ -139,20 +140,30 @@ export function generateAngularServerAppManifest(
 } {
   const serverAssetsChunks: BuildOutputFile[] = [];
   const serverAssets: Record<string, string> = {};
+  let ctx: Context | undefined;
+
   for (const file of [...additionalHtmlOutputFiles.values(), ...outputFiles]) {
     const extension = extname(file.path);
     if (extension === '.html' || (inlineCriticalCss && extension === '.css')) {
       const jsChunkFilePath = `assets-chunks/${file.path.replace(/[./]/g, '_')}.mjs`;
+      const escapedContent = escapeUnsafeChars(file.text);
+
       serverAssetsChunks.push(
         createOutputFile(
           jsChunkFilePath,
-          `export default \`${escapeUnsafeChars(file.text)}\`;`,
+          `export default \`${escapedContent}\`;`,
           BuildOutputFileType.ServerApplication,
         ),
       );
 
+      // This is needed because JavaScript engines script parser convert `\r\n` to `\n` in template literals,
+      // which can result in an incorrect byte length.
+      ctx ??= createContext({ textEncoder: new TextEncoder(), size: 0 });
+      ctx.size = 0;
+      runInContext(`size = textEncoder.encode(\`${escapedContent}\`).byteLength`, ctx);
+
       serverAssets[file.path] =
-        `{size: ${file.size}, hash: '${file.hash}', text: () => import('./${jsChunkFilePath}').then(m => m.default)}`;
+        `{size: ${ctx.size}, hash: '${file.hash}', text: () => import('./${jsChunkFilePath}').then(m => m.default)}`;
     }
   }
 

tests/legacy-cli/e2e/tests/build/server-rendering/server-routes-output-mode-server.ts

@@ -1,7 +1,7 @@
 import { join } from 'node:path';
 import { existsSync } from 'node:fs';
 import assert from 'node:assert';
-import { expectFileToMatch, writeFile } from '../../../utils/fs';
+import { expectFileToMatch, readFile, replaceInFile, writeFile } from '../../../utils/fs';
 import { execAndWaitForOutputToMatch, ng, noSilentNg, silentNg } from '../../../utils/process';
 import { installWorkspacePackages, uninstallPackage } from '../../../utils/packages';
 import { useSha } from '../../../utils/project';
@@ -20,6 +20,12 @@ export default async function () {
   await useSha();
   await installWorkspacePackages();
 
+  // Test scenario to verify that the content length, including \r\n, is accurate
+  await replaceInFile('src/app/app.component.ts', "title = '", "title = 'Title\\r\\n");
+
+  // Ensure text has been updated.
+  assert.match(await readFile('src/app/app.component.ts'), /title = 'Title/);
+
   // Add routes
   await writeFile(
     'src/app/app.routes.ts',
@@ -165,6 +171,7 @@ export default async function () {
 
   const port = await spawnServer();
   for (const [pathname, { content, headers, serverContext }] of Object.entries(responseExpects)) {
+    // NOTE: A global 'UND_ERR_SOCKET' may occur due to an incorrect Content-Length header value.
     const res = await fetch(`http://localhost:${port}${pathname}`);
     const text = await res.text();