fix(@angular-devkit/build-angular): ensure Web Worker code file is replaced in esbuild builders

The previous Web Worker bundling code for the esbuild-based builders assumed that the first
output file was the JavaScript code for the worker. While this is typically the case, when
sourcemaps are enabled it may not be. To ensure the code file is used as the replacement path
for the Worker constructor, the output files are now searched for the code file.

Author: clydin

packages/angular_devkit/build_angular/src/tools/esbuild/angular/compiler-plugin.ts

@@ -14,6 +14,7 @@ import type {
   Plugin,
   PluginBuild,
 } from 'esbuild';
+import assert from 'node:assert';
 import { realpath } from 'node:fs/promises';
 import { platform } from 'node:os';
 import * as path from 'node:path';
@@ -203,20 +204,26 @@ export function createCompilerPlugin(
               target: build.initialOptions.target,
             });
 
-            if (workerResult.errors) {
-              (result.errors ??= []).push(...workerResult.errors);
-            }
             (result.warnings ??= []).push(...workerResult.warnings);
             additionalOutputFiles.push(...workerResult.outputFiles);
             if (workerResult.metafile) {
               additionalMetafiles.push(workerResult.metafile);
             }
 
+            if (workerResult.errors.length > 0) {
+              (result.errors ??= []).push(...workerResult.errors);
+
+              // Return the original path if the build failed
+              return workerFile;
+            }
+
             // Return bundled worker file entry name to be used in the built output
-            return path.relative(
-              build.initialOptions.outdir ?? '',
-              workerResult.outputFiles[0].path,
+            const workerCodeFile = workerResult.outputFiles.find((file) =>
+              file.path.endsWith('.js'),
             );
+            assert(workerCodeFile, 'Web Worker bundled code file should always be present.');
+
+            return path.relative(build.initialOptions.outdir ?? '', workerCodeFile.path);
           },
         };
 

tests/legacy-cli/e2e/tests/build/worker.ts

@@ -10,6 +10,7 @@ import { readdir } from 'fs/promises';
 import { expectFileToExist, expectFileToMatch, replaceInFile, writeFile } from '../../utils/fs';
 import { ng } from '../../utils/process';
 import { getGlobalVariable } from '../../utils/env';
+import { expectToFail } from '../../utils/utils';
 
 export default async function () {
   const useWebpackBuilder = !getGlobalVariable('argv')['esbuild'];
@@ -33,6 +34,9 @@ export default async function () {
     const workerOutputFile = await getWorkerOutputFile(false);
     await expectFileToExist(`dist/test-project/browser/${workerOutputFile}`);
     await expectFileToMatch('dist/test-project/browser/main.js', workerOutputFile);
+    await expectToFail(() =>
+      expectFileToMatch('dist/test-project/browser/main.js', workerOutputFile + '.map'),
+    );
   }
 
   await ng('build', '--output-hashing=none');