fix(@angular-devkit/build-angular): ensure external dependencies are used by Web Worker bundling

When processing a Web Worker reference in application code, the Web Worker entry point is bundled
in a separate action. The external dependencies configuration was previously not passed on to this
action which caused the Web Worker bundling to attempt to bundle any configured external dependencies.
This could lead to build errors if the dependency does not exist within the project.

Author: clydin

packages/angular_devkit/build_angular/src/builders/application/tests/options/external-dependencies_spec.ts

@@ -38,5 +38,40 @@ describeBuilder(buildApplication, APPLICATION_BUILDER_INFO, (harness) => {
         .expectFile('dist/browser/main.js')
         .content.not.toMatch(/from ['"]@angular\/common['"]/);
     });
+
+    it('should externalize the listed depedencies in Web Workers when option is set', async () => {
+      harness.useTarget('build', {
+        ...BASE_OPTIONS,
+        externalDependencies: ['path'],
+      });
+
+      // The `path` Node.js builtin is used to cause a failure if not externalized
+      const workerCodeFile = `
+        import path from "path";
+        console.log(path);
+      `;
+
+      // Create a worker file
+      await harness.writeFile('src/app/worker.ts', workerCodeFile);
+
+      // Create app component that uses the directive
+      await harness.writeFile(
+        'src/app/app.component.ts',
+        `
+          import { Component } from '@angular/core'
+          @Component({
+            selector: 'app-root',
+            template: '<h1>Worker Test</h1>',
+          })
+          export class AppComponent {
+            worker = new Worker(new URL('./worker', import.meta.url), { type: 'module' });
+          }
+        `,
+      );
+
+      const { result } = await harness.executeOnce();
+      // If not externalized, build will fail with a Node.js platform builtin error
+      expect(result?.success).toBeTrue();
+    });
   });
 });

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

@@ -528,22 +528,19 @@ function bundleWebWorker(
 ) {
   try {
     return build.esbuild.buildSync({
+      ...build.initialOptions,
       platform: 'browser',
       write: false,
       bundle: true,
       metafile: true,
       format: 'esm',
-      mainFields: ['es2020', 'es2015', 'browser', 'module', 'main'],
-      logLevel: 'silent',
-      sourcemap: pluginOptions.sourcemap,
       entryNames: 'worker-[hash]',
       entryPoints: [workerFile],
-      absWorkingDir: build.initialOptions.absWorkingDir,
-      outdir: build.initialOptions.outdir,
-      minifyIdentifiers: build.initialOptions.minifyIdentifiers,
-      minifySyntax: build.initialOptions.minifySyntax,
-      minifyWhitespace: build.initialOptions.minifyWhitespace,
-      target: build.initialOptions.target,
+      sourcemap: pluginOptions.sourcemap,
+      // Zone.js is not used in Web workers so no need to disable
+      supported: undefined,
+      // Plugins are not supported in sync esbuild calls
+      plugins: undefined,
     });
   } catch (error) {
     if (error && typeof error === 'object' && 'errors' in error && 'warnings' in error) {