fix(@angular/cli): remove forced commonjs

Followup to #8128
Fix #9058

Author: filipesilva

packages/@angular/cli/commands/build.ts

@@ -234,11 +234,6 @@ const BuildCommand = Command.extend({
     Version.assertAngularVersionIs2_3_1OrHigher(this.project.root);
     Version.assertTypescriptVersion(this.project.root);
 
-    // Force commonjs module format for TS on dev watch builds.
-    if (commandOptions.target === 'development' && commandOptions.watch === true) {
-      commandOptions.forceTsCommonjs = true;
-    }
-
     // Add trailing slash if missing to prevent https://github.com/angular/angular-cli/issues/7295
     if (commandOptions.deployUrl && commandOptions.deployUrl.substr(-1) !== '/') {
       commandOptions.deployUrl += '/';

packages/@angular/cli/commands/serve.ts

@@ -130,11 +130,6 @@ const ServeCommand = Command.extend({
     Version.assertAngularVersionIs2_3_1OrHigher(this.project.root);
     Version.assertTypescriptVersion(this.project.root);
 
-    // Force commonjs module format for TS on dev builds.
-    if (commandOptions.target === 'development') {
-      commandOptions.forceTsCommonjs = true;
-    }
-
     // Default evalSourcemaps to true for serve. This makes rebuilds faster.
     commandOptions.evalSourcemaps = true;
 

packages/@angular/cli/commands/test.ts

@@ -24,7 +24,6 @@ export interface TestOptions {
   environment?: string;
   app?: string;
   preserveSymlinks?: boolean;
-  forceTsCommonjs?: boolean;
 }
 
 
@@ -138,12 +137,6 @@ const TestCommand = Command.extend({
       commandOptions.singleRun = true;
     }
 
-    // Don't force commonjs for code coverage builds, some setups need es2015 for it.
-    // https://github.com/angular/angular-cli/issues/5526
-    if (!commandOptions.codeCoverage) {
-      commandOptions.forceTsCommonjs = true;
-    }
-
     return testTask.run(commandOptions);
   }
 });

packages/@angular/cli/models/build-options.ts

@@ -30,7 +30,6 @@ export interface BuildOptions {
   buildOptimizer?: boolean;
   namedChunks?: boolean;
   subresourceIntegrity?: boolean;
-  forceTsCommonjs?: boolean;
   serviceWorker?: boolean;
   skipAppShell?: boolean;
 }

packages/@angular/cli/models/webpack-config.ts

@@ -47,9 +47,6 @@ export class NgCliWebpackConfig<T extends BuildOptions = BuildOptions> {
     const supportES2015 = tsConfig.options.target !== projectTs.ScriptTarget.ES3
                         && tsConfig.options.target !== projectTs.ScriptTarget.ES5;
 
-    // TODO: Remove this functionality completely as it is no longer needed with Webpack 4
-    buildOptions.forceTsCommonjs = false;
-
     this.wco = { projectRoot, buildOptions, appConfig, tsConfig, supportES2015 };
   }
 

packages/@angular/cli/models/webpack-configs/typescript.ts

@@ -24,12 +24,6 @@ function _createAotPlugin(wco: WebpackConfigOptions, options: any, useMain = tru
     options.compilerOptions.preserveSymlinks = true;
   }
 
-  // Forcing commonjs seems to drastically improve rebuild speeds on webpack.
-  // Dev builds on watch mode will set this option to true.
-  if (wco.buildOptions.forceTsCommonjs) {
-    options.compilerOptions.module = 'commonjs';
-  }
-
   // Read the environment, and set it in the compiler host.
   let hostReplacementPaths: any = {};
   // process environment file replacement

packages/@angular/cli/tasks/test.ts

@@ -44,7 +44,6 @@ export default Task.extend({
         poll: options.poll,
         environment: options.environment,
         preserveSymlinks: options.preserveSymlinks,
-        forceTsCommonjs: options.forceTsCommonjs,
         app: options.app
       };