refactor(@angular-devkit/build-angular): properly display errors originating in ESM loader hooks

Currently, errors occurring in ESM loader hooks while using `--import` are not correctly displayed, as they cannot be transferred from the worker to the main thread. Although the error is an instance of Error, it contains non-transferable properties and cannot be transmitted from a worker when --import is used. Consequently, when read outside of the worker, the error object displays as `[Object object]`. To address this issue, we reconstruct the error message.

See: #27251
(cherry picked from commit 51debcd)

Author: alan-agius4

packages/angular_devkit/build_angular/src/utils/server-rendering/load-esm-from-memory.ts

@@ -0,0 +1,33 @@
+/**
+ * @license
+ * Copyright Google LLC All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+import { assertIsError } from '../error';
+import { loadEsmModule } from '../load-esm';
+import { MainServerBundleExports, RenderUtilsServerBundleExports } from './main-bundle-exports';
+
+export function loadEsmModuleFromMemory(
+  path: './main.server.mjs',
+): Promise<MainServerBundleExports>;
+export function loadEsmModuleFromMemory(
+  path: './render-utils.server.mjs',
+): Promise<RenderUtilsServerBundleExports>;
+export function loadEsmModuleFromMemory(path: string): Promise<unknown> {
+  return loadEsmModule(new URL(path, 'memory://')).catch((e) => {
+    assertIsError(e);
+
+    // While the error is an 'instanceof Error', it is extended with non transferable properties
+    // and cannot be transferred from a worker when using `--import`. This results in the error object
+    // displaying as '[Object object]' when read outside of the worker. Therefore, we reconstruct the error message here.
+    const error: Error & { code?: string } = new Error(e.message);
+    error.stack = e.stack;
+    error.name = e.name;
+    error.code = e.code;
+
+    throw error;
+  });
+}

packages/angular_devkit/build_angular/src/utils/server-rendering/render-page.ts

@@ -9,7 +9,7 @@
 import type { ApplicationRef, StaticProvider } from '@angular/core';
 import assert from 'node:assert';
 import { basename } from 'node:path';
-import { loadEsmModule } from '../load-esm';
+import { loadEsmModuleFromMemory } from './load-esm-from-memory';
 import { MainServerBundleExports, RenderUtilsServerBundleExports } from './main-bundle-exports';
 
 export interface RenderOptions {
@@ -39,7 +39,7 @@ export async function renderPage({
   document,
   inlineCriticalCss,
   outputFiles,
-  loadBundle = loadEsmModule,
+  loadBundle = loadEsmModuleFromMemory,
 }: RenderOptions): Promise<RenderResult> {
   const { default: bootstrapAppFnOrModule } = await loadBundle('./main.server.mjs');
   const { ɵSERVER_CONTEXT, renderModule, renderApplication, ɵresetCompiledComponents, ɵConsole } =

packages/angular_devkit/build_angular/src/utils/server-rendering/render-worker.ts

@@ -7,7 +7,6 @@
  */
 
 import { workerData } from 'node:worker_threads';
-import { loadEsmModule } from '../load-esm';
 import type { ESMInMemoryFileLoaderWorkerData } from './esm-in-memory-loader/loader-hooks';
 import { patchFetchToLoadInMemoryAssets } from './fetch-patch';
 import { RenderResult, ServerContext, renderPage } from './render-page';
@@ -35,7 +34,6 @@ function render(options: RenderOptions): Promise<RenderResult> {
     outputFiles,
     document,
     inlineCriticalCss,
-    loadBundle: async (path) => await loadEsmModule(new URL(path, 'memory://')),
   });
 }
 

packages/angular_devkit/build_angular/src/utils/server-rendering/routes-extractor-worker.ts

@@ -7,10 +7,9 @@
  */
 
 import { workerData } from 'node:worker_threads';
-import { loadEsmModule } from '../load-esm';
 import type { ESMInMemoryFileLoaderWorkerData } from './esm-in-memory-loader/loader-hooks';
 import { patchFetchToLoadInMemoryAssets } from './fetch-patch';
-import { MainServerBundleExports, RenderUtilsServerBundleExports } from './main-bundle-exports';
+import { loadEsmModuleFromMemory } from './load-esm-from-memory';
 
 export interface RoutesExtractorWorkerData extends ESMInMemoryFileLoaderWorkerData {
   document: string;
@@ -30,12 +29,8 @@ const { document, verbose } = workerData as RoutesExtractorWorkerData;
 
 /** Renders an application based on a provided options. */
 async function extractRoutes(): Promise<RoutersExtractorWorkerResult> {
-  const { extractRoutes } = await loadEsmModule<RenderUtilsServerBundleExports>(
-    new URL('./render-utils.server.mjs', 'memory://'),
-  );
-  const { default: bootstrapAppFnOrModule } = await loadEsmModule<MainServerBundleExports>(
-    new URL('./main.server.mjs', 'memory://'),
-  );
+  const { extractRoutes } = await loadEsmModuleFromMemory('./render-utils.server.mjs');
+  const { default: bootstrapAppFnOrModule } = await loadEsmModuleFromMemory('./main.server.mjs');
 
   const skippedRedirects: string[] = [];
   const skippedOthers: string[] = [];