fix(@angular-devkit/build-angular): server build is generating un-needed polyfill file

Fixes #14655

Author: Alan

packages/angular_devkit/build_angular/src/angular-cli-files/models/webpack-configs/common.ts

@@ -66,42 +66,43 @@ export function getCommonConfig(wco: WebpackConfigOptions): Configuration {
     entryPoints['main'] = [path.resolve(root, buildOptions.main)];
   }
 
-  const es5Polyfills = path.join(__dirname, '..', 'es5-polyfills.js');
-  const es5JitPolyfills = path.join(__dirname, '..', 'es5-jit-polyfills.js');
-
-  if (targetInFileName) {
-    // For differential loading we don't need to have 2 polyfill bundles
-    if (buildOptions.scriptTargetOverride === ScriptTarget.ES2015) {
-      entryPoints['polyfills'] = [path.join(__dirname, '..', 'safari-nomodule.js')];
-    } else {
-      entryPoints['polyfills'] = [es5Polyfills];
-      if (!buildOptions.aot) {
-        entryPoints['polyfills'].push(es5JitPolyfills);
+  if (wco.buildOptions.platform !== 'server') {
+    const es5Polyfills = path.join(__dirname, '..', 'es5-polyfills.js');
+    const es5JitPolyfills = path.join(__dirname, '..', 'es5-jit-polyfills.js');
+    if (targetInFileName) {
+      // For differential loading we don't need to have 2 polyfill bundles
+      if (buildOptions.scriptTargetOverride === ScriptTarget.ES2015) {
+        entryPoints['polyfills'] = [path.join(__dirname, '..', 'safari-nomodule.js')];
+      } else {
+        entryPoints['polyfills'] = [es5Polyfills];
+        if (!buildOptions.aot) {
+          entryPoints['polyfills'].push(es5JitPolyfills);
+        }
       }
-    }
-  } else {
-    // For NON differential loading we want to have 2 polyfill bundles
-    if (buildOptions.es5BrowserSupport
-      || (buildOptions.es5BrowserSupport === undefined && isEs5SupportNeeded(projectRoot))) {
-      entryPoints['polyfills-es5'] = [es5Polyfills];
-      if (!buildOptions.aot) {
-        entryPoints['polyfills-es5'].push(es5JitPolyfills);
+    } else {
+      // For NON differential loading we want to have 2 polyfill bundles
+      if (buildOptions.es5BrowserSupport
+        || (buildOptions.es5BrowserSupport === undefined && isEs5SupportNeeded(projectRoot))) {
+        entryPoints['polyfills-es5'] = [es5Polyfills];
+        if (!buildOptions.aot) {
+          entryPoints['polyfills-es5'].push(es5JitPolyfills);
+        }
       }
     }
-  }
 
-  if (buildOptions.polyfills) {
-    entryPoints['polyfills'] = [
-      ...(entryPoints['polyfills'] || []),
-      path.resolve(root, buildOptions.polyfills),
-    ];
-  }
+    if (buildOptions.polyfills) {
+      entryPoints['polyfills'] = [
+        ...(entryPoints['polyfills'] || []),
+        path.resolve(root, buildOptions.polyfills),
+      ];
+    }
 
-  if (!buildOptions.aot) {
-    entryPoints['polyfills'] = [
-      ...(entryPoints['polyfills'] || []),
-      path.join(__dirname, '..', 'jit-polyfills.js'),
-    ];
+    if (!buildOptions.aot) {
+      entryPoints['polyfills'] = [
+        ...(entryPoints['polyfills'] || []),
+        path.join(__dirname, '..', 'jit-polyfills.js'),
+      ];
+    }
   }
 
   if (buildOptions.profile || process.env['NG_BUILD_PROFILING']) {

packages/angular_devkit/build_angular/test/server/base_spec_large.ts

@@ -7,7 +7,7 @@
  */
 
 import { Architect } from '@angular-devkit/architect';
-import { join, normalize, virtualFs } from '@angular-devkit/core';
+import { getSystemPath, join, normalize, virtualFs } from '@angular-devkit/core';
 import { take, tap } from 'rxjs/operators';
 import { BrowserBuilderOutput } from '../../src/browser';
 import { createArchitect, host } from '../utils';
@@ -37,6 +37,34 @@ describe('Server Builder', () => {
     await run.stop();
   });
 
+  it('should not emit polyfills', async () => {
+    const run = await architect.scheduleTarget(target);
+    const output = await run.result as BrowserBuilderOutput;
+    expect(output.success).toBe(true);
+
+    expect(host.fileMatchExists(getSystemPath(outputPath), /polyfills/)).not.toBeDefined();
+    expect(host.fileMatchExists(getSystemPath(outputPath), /main/)).toBeDefined();
+
+    await run.stop();
+  });
+
+  it('should not emit polyfills when ES5 support is needed', async () => {
+    // the below is needed because of different code paths
+    // for polyfills if differential loading is needed
+    host.writeMultipleFiles({
+      'browserslist': 'IE 10',
+    });
+
+    const run = await architect.scheduleTarget(target);
+    const output = await run.result as BrowserBuilderOutput;
+    expect(output.success).toBe(true);
+
+    expect(host.fileMatchExists(getSystemPath(outputPath), /polyfills/)).not.toBeDefined();
+    expect(host.fileMatchExists(getSystemPath(outputPath), /main/)).toBeDefined();
+
+    await run.stop();
+  });
+
   it('supports sourcemaps', async () => {
     const overrides = { sourceMap: true };