fix(@angular-devkit/build-angular): don't double process factory files

Author: filipesilva

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

@@ -468,6 +468,8 @@ export function getCommonConfig(wco: WebpackConfigOptions): Configuration {
         },
         {
           test: /\.js$/,
+          // Factory files are processed by BO in the rules added in typescript.ts.
+          exclude: /(ngfactory|ngstyle)\.js$/,
           ...buildOptimizerUseRule,
         },
         {

packages/ngtools/webpack/src/compiler_host.ts

@@ -144,7 +144,7 @@ export class WebpackCompilerHost implements ts.CompilerHost {
     if (!exists) {
       // At this point we're only looking at resource files (html/css/scss/etc).
       // If the original was deleted, we should delete the virtual files too.
-      // If the original it wasn't deleted we should leave them to be overwritten, because webpack
+      // If the original wasn't deleted we should leave them to be overwritten, because webpack
       // might begin the loading process before our plugin has re-emitted them.
       for (const ext of this._virtualStyleFileExtensions) {
         const virtualFile = (fullPath + ext) as Path;