fix(@angular-devkit/build-angular): only copy assets outside of webpack when differential loading is needed in build builder

Fixes #15825

Author: alan-agius4

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

@@ -40,8 +40,6 @@ const ProgressPlugin = require('webpack/lib/ProgressPlugin');
 const CircularDependencyPlugin = require('circular-dependency-plugin');
 const TerserPlugin = require('terser-webpack-plugin');
 
-// tslint:disable-next-line:no-any
-const g: any = typeof global !== 'undefined' ? global : {};
 
 // tslint:disable-next-line:no-big-function
 export function getCommonConfig(wco: WebpackConfigOptions): Configuration {
@@ -242,10 +240,7 @@ export function getCommonConfig(wco: WebpackConfigOptions): Configuration {
   }
 
   // process asset entries
-  if (
-    buildOptions.assets &&
-    (fullDifferential || buildOptions.watch || !differentialLoadingNeeded)
-  ) {
+  if (buildOptions.assets.length) {
     const copyWebpackPluginPatterns = buildOptions.assets.map((asset: AssetPatternClass) => {
       // Resolve input paths relative to workspace root and add slash at the end.
       asset.input = path.resolve(root, asset.input).replace(/\\/g, '/');

packages/angular_devkit/build_angular/src/browser/index.ts

@@ -13,17 +13,14 @@ import {
   runWebpack,
 } from '@angular-devkit/build-webpack';
 import {
-  getSystemPath,
   join,
   json,
   logging,
   normalize,
-  resolve,
   tags,
   virtualFs,
 } from '@angular-devkit/core';
 import { NodeJsSyncHost } from '@angular-devkit/core/node';
-import { createHash } from 'crypto';
 import * as findCacheDirectory from 'find-cache-dir';
 import * as fs from 'fs';
 import * as path from 'path';
@@ -81,9 +78,7 @@ import {
 import { BundleActionExecutor } from './action-executor';
 import { Schema as BrowserBuilderSchema } from './schema';
 
-const cacache = require('cacache');
 const cacheDownlevelPath = findCacheDirectory({ name: 'angular-build-dl' });
-const packageVersion = require('../../package.json').version;
 
 export type BrowserBuilderOutput = json.JsonObject &
   BuilderOutput & {

packages/angular_devkit/build_angular/src/utils/webpack-browser-config.ts

@@ -106,6 +106,8 @@ export async function generateWebpackConfig(
     } else if (differentialLoading && !fullDifferential) {
       buildOptions = {
         ...options,
+        // Under downlevel differential loading we copy the assets outside of webpack.
+        assets: [],
         esVersionInFileName: true,
         scriptTargetOverride: ts.ScriptTarget.ES5,
         es5BrowserSupport: undefined,