From 19ef42a37e705cc81ec18a04fc69d01e14937136 Mon Sep 17 00:00:00 2001
From: Alan Agius <alan.agius4@gmail.com>
Date: Fri, 28 May 2021 07:49:57 +0200
Subject: [PATCH] fix(@angular-devkit/build-angular): do not resolve
 web-workers in server builds

Web-workers are not supported on the server and therefore we should not try include them in server builds.

Closes #20877

(cherry picked from commit 77f81dc7f72c218e3b26c92c15b927b505f91240)
---
 .../build_angular/src/server/base_spec.ts     | 27 +++++++++++++++++++
 .../src/webpack/configs/server.ts             |  8 ++++++
 2 files changed, 35 insertions(+)

diff --git a/packages/angular_devkit/build_angular/src/server/base_spec.ts b/packages/angular_devkit/build_angular/src/server/base_spec.ts
index 859d7d389b29..e38c741a5658 100644
--- a/packages/angular_devkit/build_angular/src/server/base_spec.ts
+++ b/packages/angular_devkit/build_angular/src/server/base_spec.ts
@@ -146,4 +146,31 @@ describe('Server Builder', () => {
 
     await run.stop();
   });
+
+  it('should not try to resolve web-worker', async () => {
+    host.writeMultipleFiles({
+      'src/app/app.worker.ts': `
+        /// <reference lib="webworker" />
+  
+        const foo: string = 'hello world';
+        addEventListener('message', ({ data }) => {
+          postMessage(foo);
+        });
+      `,
+      'src/main.server.ts': `
+        if (typeof Worker !== 'undefined') {
+          const worker = new Worker(new URL('./app/app.worker', import.meta.url), { type: 'module' });
+          worker.onmessage = ({ data }) => {
+            console.log('page got message:', data);
+          };
+          worker.postMessage('hello');
+        }
+      `,
+    });
+
+    const run = await architect.scheduleTarget(target);
+    const output = (await run.result) as ServerBuilderOutput;
+    expect(output.success).toBe(true);
+    await run.stop();
+  });
 });
diff --git a/packages/angular_devkit/build_angular/src/webpack/configs/server.ts b/packages/angular_devkit/build_angular/src/webpack/configs/server.ts
index 0364fe72704e..9e28d25131da 100644
--- a/packages/angular_devkit/build_angular/src/webpack/configs/server.ts
+++ b/packages/angular_devkit/build_angular/src/webpack/configs/server.ts
@@ -39,6 +39,14 @@ export function getServerConfig(wco: WebpackConfigOptions): Configuration {
     output: {
       libraryTarget: 'commonjs',
     },
+    module: {
+      parser: {
+        javascript: {
+          worker: false,
+          url: false,
+        },
+      },
+    },
     plugins: [
       // Fixes Critical dependency: the request of a dependency is an expression
       new ContextReplacementPlugin(/@?hapi(\\|\/)/),