fix: add optional section to make appshell work with lazy-loading and ssr (#646)

At the moment, there is no clear explaination how to make an app-shell work togather with SSR and lazy loading.

See for more context angular/angular-cli#9202

Author: alan-agius4

server.ts

@@ -1,13 +1,14 @@
 import 'zone.js/dist/zone-node';
 import 'reflect-metadata';
-import {enableProdMode} from '@angular/core';
+import { enableProdMode } from '@angular/core';
+
 // Express Engine
-import {ngExpressEngine} from '@nguniversal/express-engine';
+import { ngExpressEngine } from '@nguniversal/express-engine';
 // Import module map for lazy loading
-import {provideModuleMap} from '@nguniversal/module-map-ngfactory-loader';
+import { provideModuleMap } from '@nguniversal/module-map-ngfactory-loader';
 
 import * as express from 'express';
-import {join} from 'path';
+import { join } from 'path';
 
 // Faster server renders w/ Prod mode (dev mode never needed)
 enableProdMode();
@@ -19,13 +20,23 @@ const PORT = process.env.PORT || 4000;
 const DIST_FOLDER = join(process.cwd(), 'dist');
 
 // * NOTE :: leave this as require() since this file is built Dynamically from webpack
-const {AppServerModuleNgFactory, LAZY_MODULE_MAP} = require('./server/main');
+const { AppServerModuleNgFactory, LAZY_MODULE_MAP } = require('./server/main');
 
 // Our Universal express-engine (found @ https://github.com/angular/universal/tree/master/modules/express-engine)
 app.engine('html', ngExpressEngine({
   bootstrap: AppServerModuleNgFactory,
   providers: [
-    provideModuleMap(LAZY_MODULE_MAP)
+    provideModuleMap(LAZY_MODULE_MAP),
+    // In case you want to use an AppShell with SSR and Lazy loading
+    // you'd need to uncomment the below. (see: https://github.com/angular/angular-cli/issues/9202)
+    // {
+    //   provide: NgModuleFactoryLoader,
+    //   useClass: ModuleMapNgFactoryLoader,
+    //   deps: [
+    //     Compiler,
+    //     MODULE_MAP
+    //   ],
+    // },
   ]
 }));