refactor(@angular/build): add NG_BUILD_PARTIAL_SSR environment variable to disable prerendering and manifest generation

packages/angular/build/src/builders/application/execute-post-bundle.ts

@@ -70,7 +70,7 @@ export async function executePostBundleSteps(
     prerenderOptions,
     appShellOptions,
     workspaceRoot,
-    disableFullServerManifestGeneration,
+    partialSSRBuild,
   } = options;
 
   // Index HTML content without CSS inlining to be used for server rendering (AppShell, SSG and SSR).
@@ -125,7 +125,7 @@ export async function executePostBundleSteps(
   // Pre-render (SSG) and App-shell
   // If localization is enabled, prerendering is handled in the inlining process.
   if (
-    !disableFullServerManifestGeneration &&
+    !partialSSRBuild &&
     (prerenderOptions || appShellOptions || (outputMode && serverEntryPoint)) &&
     !allErrors.length
   ) {

packages/angular/build/src/builders/application/index.ts

@@ -88,15 +88,15 @@ export async function* buildApplicationInternal(
 
   yield* runEsBuildBuildAction(
     async (rebuildState) => {
-      const { serverEntryPoint, jsonLogs, disableFullServerManifestGeneration } = normalizedOptions;
+      const { serverEntryPoint, jsonLogs, partialSSRBuild } = normalizedOptions;
 
       const startTime = process.hrtime.bigint();
       const result = await executeBuild(normalizedOptions, context, rebuildState);
 
       if (jsonLogs) {
         result.addLog(await createJsonBuildManifest(result, normalizedOptions));
       } else {
-        if (serverEntryPoint && !disableFullServerManifestGeneration) {
+        if (serverEntryPoint && !partialSSRBuild) {
           const prerenderedRoutesLength = Object.keys(result.prerenderedRoutes).length;
           let prerenderMsg = `Prerendered ${prerenderedRoutesLength} static route`;
           prerenderMsg += prerenderedRoutesLength !== 1 ? 's.' : '.';

packages/angular/build/src/builders/application/options.ts

@@ -14,7 +14,7 @@ import { createRequire } from 'node:module';
 import path from 'node:path';
 import { normalizeAssetPatterns, normalizeOptimization, normalizeSourceMaps } from '../../utils';
 import { supportColor } from '../../utils/color';
-import { useJSONBuildLogs } from '../../utils/environment-options';
+import { useJSONBuildLogs, usePartialSsrBuild } from '../../utils/environment-options';
 import { I18nOptions, createI18nOptions } from '../../utils/i18n-options';
 import { IndexHtmlTransform } from '../../utils/index-file/index-html-generator';
 import { normalizeCacheOptions } from '../../utils/normalize-cache';
@@ -82,14 +82,12 @@ interface InternalOptions {
   forceI18nFlatOutput?: boolean;
 
   /**
-   * When set to `true`, disables the generation of a full manifest with routes.
-   *
-   * This option is primarily used during development to improve performance,
-   * as the full manifest is generated at runtime when using the development server.
+   * When set to `true`, enables fast SSR in development mode by disabling the full manifest generation and prerendering.
    *
+   * This option is intended to optimize performance during development by skipping prerendering and route extraction when not required.
    * @default false
    */
-  disableFullServerManifestGeneration?: boolean;
+  partialSSRBuild?: boolean;
 
   /**
    * Enables the use of AOT compiler emitted external runtime styles.
@@ -382,7 +380,7 @@ export async function normalizeOptions(
     deployUrl,
     clearScreen,
     define,
-    disableFullServerManifestGeneration = false,
+    partialSSRBuild = false,
     externalRuntimeStyles,
   } = options;
 
@@ -444,7 +442,7 @@ export async function normalizeOptions(
     colors: supportColor(),
     clearScreen,
     define,
-    disableFullServerManifestGeneration,
+    partialSSRBuild: usePartialSsrBuild || partialSSRBuild,
     externalRuntimeStyles,
   };
 }

packages/angular/build/src/builders/dev-server/vite-server.ts

@@ -110,7 +110,7 @@ export async function* serveWithVite(
 
   // Disable generating a full manifest with routes.
   // This is done during runtime when using the dev-server.
-  browserOptions.disableFullServerManifestGeneration = true;
+  browserOptions.partialSSRBuild = true;
 
   // The development server currently only supports a single locale when localizing.
   // This matches the behavior of the Webpack-based development server but could be expanded in the future.

packages/angular/build/src/utils/environment-options.ts

@@ -104,3 +104,7 @@ export const shouldOptimizeChunks =
 const hmrComponentStylesVariable = process.env['NG_HMR_CSTYLES'];
 export const useComponentStyleHmr =
   isPresent(hmrComponentStylesVariable) && isEnabled(hmrComponentStylesVariable);
+
+const partialSsrBuildVariable = process.env['NG_BUILD_PARTIAL_SSR'];
+export const usePartialSsrBuild =
+  isPresent(partialSsrBuildVariable) && isEnabled(partialSsrBuildVariable);