fix(@angular-devkit/build-angular): only generate server directory when SSR is enabled

Previously, the `server` directory was erroneously generated even in instances where SSG was enabled but SSR remained inactive.

Author: alan-agius4

packages/angular_devkit/build_angular/src/builders/application/build-action.ts

@@ -21,7 +21,7 @@ import {
 import { deleteOutputDir } from '../../utils/delete-output-dir';
 import { shouldWatchRoot } from '../../utils/environment-options';
 import { NormalizedCachedOptions } from '../../utils/normalize-cache';
-import { NormalizedOutputOptions } from './options';
+import { NormalizedApplicationBuildOptions, NormalizedOutputOptions } from './options';
 
 // Watch workspace for package manager changes
 const packageWatchFiles = [
@@ -37,6 +37,9 @@ const packageWatchFiles = [
   '.pnp.data.json',
 ];
 
+type BuildActionOutput = (ExecutionResult['outputWithFiles'] | ExecutionResult['output']) &
+  BuilderOutput;
+
 export async function* runEsBuildBuildAction(
   action: (rebuildState?: RebuildState) => Promise<ExecutionResult>,
   options: {
@@ -58,7 +61,7 @@ export async function* runEsBuildBuildAction(
     colors?: boolean;
     jsonLogs?: boolean;
   },
-): AsyncIterable<(ExecutionResult['outputWithFiles'] | ExecutionResult['output']) & BuilderOutput> {
+): AsyncIterable<BuildActionOutput> {
   const {
     writeToFileSystemFilter,
     writeToFileSystem,
@@ -153,16 +156,7 @@ export async function* runEsBuildBuildAction(
   // Output the first build results after setting up the watcher to ensure that any code executed
   // higher in the iterator call stack will trigger the watcher. This is particularly relevant for
   // unit tests which execute the builder and modify the file system programmatically.
-  if (writeToFileSystem) {
-    // Write output files
-    await writeResultFiles(result.outputFiles, result.assetFiles, outputOptions);
-
-    yield result.output;
-  } else {
-    // Requires casting due to unneeded `JsonObject` requirement. Remove once fixed.
-    // eslint-disable-next-line @typescript-eslint/no-explicit-any
-    yield result.outputWithFiles as any;
-  }
+  yield await writeAndEmitOutput(writeToFileSystem, result, outputOptions, writeToFileSystemFilter);
 
   // Finish if watch mode is not enabled
   if (!watcher) {
@@ -212,19 +206,12 @@ export async function* runEsBuildBuildAction(
         watcher.remove([...staleWatchFiles]);
       }
 
-      if (writeToFileSystem) {
-        // Write output files
-        const filesToWrite = writeToFileSystemFilter
-          ? result.outputFiles.filter(writeToFileSystemFilter)
-          : result.outputFiles;
-        await writeResultFiles(filesToWrite, result.assetFiles, outputOptions);
-
-        yield result.output;
-      } else {
-        // Requires casting due to unneeded `JsonObject` requirement. Remove once fixed.
-        // eslint-disable-next-line @typescript-eslint/no-explicit-any
-        yield result.outputWithFiles as any;
-      }
+      yield await writeAndEmitOutput(
+        writeToFileSystem,
+        result,
+        outputOptions,
+        writeToFileSystemFilter,
+      );
     }
   } finally {
     // Stop the watcher and cleanup incremental rebuild state
@@ -233,3 +220,25 @@ export async function* runEsBuildBuildAction(
     shutdownSassWorkerPool();
   }
 }
+
+async function writeAndEmitOutput(
+  writeToFileSystem: boolean,
+  { outputFiles, output, outputWithFiles, assetFiles }: ExecutionResult,
+  outputOptions: NormalizedApplicationBuildOptions['outputOptions'],
+  writeToFileSystemFilter: ((file: BuildOutputFile) => boolean) | undefined,
+): Promise<BuildActionOutput> {
+  if (writeToFileSystem) {
+    // Write output files
+    const outputFilesToWrite = writeToFileSystemFilter
+      ? outputFiles.filter(writeToFileSystemFilter)
+      : outputFiles;
+
+    await writeResultFiles(outputFilesToWrite, assetFiles, outputOptions);
+
+    return output;
+  } else {
+    // Requires casting due to unneeded `JsonObject` requirement. Remove once fixed.
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+    return outputWithFiles as any;
+  }
+}

packages/angular_devkit/build_angular/src/builders/application/tests/options/ssr_spec.ts

@@ -50,5 +50,47 @@ describeBuilder(buildApplication, APPLICATION_BUILDER_INFO, (harness) => {
       expect(result?.success).toBeTrue();
       harness.expectFile('dist/server/server.mjs').toExist();
     });
+
+    it(`should emit 'server' directory when 'ssr' is 'true'`, async () => {
+      await harness.writeFile('file.mjs', `console.log('Hello!');`);
+
+      harness.useTarget('build', {
+        ...BASE_OPTIONS,
+        server: 'src/main.server.ts',
+        ssr: true,
+      });
+
+      const { result } = await harness.executeOnce();
+      expect(result?.success).toBeTrue();
+      harness.expectDirectory('dist/server').toExist();
+    });
+
+    it(`should not emit 'server' directory when 'ssr' is 'false'`, async () => {
+      await harness.writeFile('file.mjs', `console.log('Hello!');`);
+
+      harness.useTarget('build', {
+        ...BASE_OPTIONS,
+        server: 'src/main.server.ts',
+        ssr: false,
+      });
+
+      const { result } = await harness.executeOnce();
+      expect(result?.success).toBeTrue();
+      harness.expectDirectory('dist/server').toNotExist();
+    });
+
+    it(`should not emit 'server' directory when 'ssr' is not set`, async () => {
+      await harness.writeFile('file.mjs', `console.log('Hello!');`);
+
+      harness.useTarget('build', {
+        ...BASE_OPTIONS,
+        server: 'src/main.server.ts',
+        ssr: undefined,
+      });
+
+      const { result } = await harness.executeOnce();
+      expect(result?.success).toBeTrue();
+      harness.expectDirectory('dist/server').toNotExist();
+    });
   });
 });

packages/angular_devkit/build_angular/src/tools/esbuild/utils.ts

@@ -217,7 +217,7 @@ export function getFeatureSupport(target: string[]): BuildOptions['supported'] {
 export async function writeResultFiles(
   outputFiles: BuildOutputFile[],
   assetFiles: BuildOutputAsset[] | undefined,
-  { base, browser, media, server }: NormalizedOutputOptions,
+  { base, browser, server }: NormalizedOutputOptions,
 ) {
   const directoryExists = new Set<string>();
   const ensureDirectoryExists = async (destPath: string) => {