feat(@angular-devkit/build-angular): enable localize support for SSR with application builder

With the output path directory structure updates in place, the localize support for SSR has
now been enabled. This allows for the `application` builder to produce both browser and server
output that is localized based on the i18n configuration for the project.

Author: clydin

packages/angular_devkit/build_angular/src/builders/application/index.ts

@@ -44,14 +44,6 @@ export async function* buildApplicationInternal(
 
   const normalizedOptions = await normalizeOptions(context, projectName, options);
 
-  // Warn about SSR not yet supporting localize
-  if (normalizedOptions.i18nOptions.shouldInline && normalizedOptions.ssrOptions) {
-    context.logger.warn(
-      `SSR is not yet supported with the 'localize' option and will be disabled for this build.`,
-    );
-    normalizedOptions.ssrOptions = undefined;
-  }
-
   yield* runEsBuildBuildAction(
     (rebuildState) => executeBuild(normalizedOptions, context, rebuildState),
     {

tests/legacy-cli/e2e/tests/i18n/ivy-localize-ssr.ts

@@ -0,0 +1,111 @@
+import { readFileSync, readdirSync } from 'node:fs';
+import { getGlobalVariable } from '../../utils/env';
+import { copyFile, expectFileToMatch, replaceInFile, writeFile } from '../../utils/fs';
+import { installWorkspacePackages, uninstallPackage } from '../../utils/packages';
+import { ng } from '../../utils/process';
+import { updateJsonFile, useSha } from '../../utils/project';
+import { readNgVersion } from '../../utils/version';
+
+const snapshots = require('../../ng-snapshot/package.json');
+
+export default async function () {
+  const useWebpackBuilder = !getGlobalVariable('argv')['esbuild'];
+  if (useWebpackBuilder) {
+    // This test is for the `application` builder only
+    return;
+  }
+
+  const isSnapshotBuild = getGlobalVariable('argv')['ng-snapshots'];
+  await updateJsonFile('package.json', (packageJson) => {
+    const dependencies = packageJson['dependencies'];
+    dependencies['@angular/localize'] = isSnapshotBuild
+      ? snapshots.dependencies['@angular/localize']
+      : readNgVersion();
+  });
+
+  // forcibly remove in case another test doesn't clean itself up
+  await uninstallPackage('@angular/ssr');
+
+  await ng('add', '@angular/ssr', '--skip-confirmation', '--skip-install');
+
+  await useSha();
+  await installWorkspacePackages();
+
+  // Set configurations for each locale.
+  const langTranslations = [
+    { lang: 'en-US', translation: 'Hello i18n!' },
+    { lang: 'fr', translation: 'Bonjour i18n!' },
+  ];
+
+  await updateJsonFile('angular.json', (workspaceJson) => {
+    const appProject = workspaceJson.projects['test-project'];
+    const appArchitect = appProject.architect || appProject.targets;
+    const buildOptions = appArchitect['build'].options;
+
+    // Enable localization for all locales
+    buildOptions.localize = true;
+
+    // Add locale definitions to the project
+    const i18n: Record<string, any> = (appProject.i18n = { locales: {} });
+    for (const { lang } of langTranslations) {
+      if (lang == 'en-US') {
+        i18n.sourceLocale = lang;
+      } else {
+        i18n.locales[lang] = `src/locale/messages.${lang}.xlf`;
+      }
+    }
+  });
+
+  // Add a translatable element
+  // Extraction of i18n only works on browser targets.
+  // Let's add the same translation that there is in the app-shell
+  await writeFile(
+    'src/app/app.component.html',
+    '<h1 i18n="An introduction header for this sample">Hello i18n!</h1>',
+  );
+
+  // Extract the translation messages and copy them for each language.
+  await ng('extract-i18n', '--output-path=src/locale');
+  await expectFileToMatch('src/locale/messages.xlf', `source-language="en-US"`);
+  await expectFileToMatch('src/locale/messages.xlf', `An introduction header for this sample`);
+
+  for (const { lang, translation } of langTranslations) {
+    if (lang != 'en-US') {
+      await copyFile('src/locale/messages.xlf', `src/locale/messages.${lang}.xlf`);
+      await replaceInFile(
+        `src/locale/messages.${lang}.xlf`,
+        'source-language="en-US"',
+        `source-language="en-US" target-language="${lang}"`,
+      );
+      await replaceInFile(
+        `src/locale/messages.${lang}.xlf`,
+        '<source>Hello i18n!</source>',
+        `<source>Hello i18n!</source>\n<target>${translation}</target>`,
+      );
+    }
+  }
+
+  // Build each locale and verify the output.
+  await ng('build', '--output-hashing=none');
+
+  for (const { lang, translation } of langTranslations) {
+    let foundTranslation = false;
+
+    // The translation may be in any of the lazy-loaded generated chunks
+    for (const entry of readdirSync(`dist/test-project/server/${lang}/`)) {
+      if (!entry.endsWith('.mjs')) {
+        continue;
+      }
+
+      const contents = readFileSync(`dist/test-project/server/${lang}/${entry}`, 'utf-8');
+      foundTranslation ||= contents.includes(translation);
+      if (foundTranslation) {
+        break;
+      }
+    }
+
+    if (!foundTranslation) {
+      throw new Error(`Translation not found in 'dist/test-project/server/${lang}/'`);
+    }
+  }
+}