Lazy loading

As I mentioned earlier NgModules are not just the units of compilation, they are also the units of distribution. That is why we bootstrap a NgModule, and not a component—we don't distribute components, we distribute modules. And that's why we lazy load NgModules as well.

import {NgModuleFactoryLoader, Injector} from '@angular/core';

class MyService {
  constructor(loader: NgModuleFactoryLoader, injector: Injector) {
    loader.load("mymodule").then((f: NgModuleFactory) => {
      const moduleRef = f.create(injector);
      moduleRef.injector; // module injector
      moduleRef.componentFactoryResolver; // all the \
components factories of the lazy-loaded module
    });
  }
}

The loader compiles the modules if the application is running in the JIT mode, and does not in the AOT mode. The default loader @angular/core ships with uses SystemJS, but, as most things in Angular...