app.component.ts

import {
  Component,
  ɵrenderComponent as renderComponent,
  Injector,
  ɵLifecycleHooksFeature as LifecycleHooksFeature
} from '@angular/core';

@Component({
  selector: 'app-root',
  template: `
    <app-button></app-button>
  `
})
export class AppComponent {
  constructor(injector: Injector) {
    import('./button.component').then(({ ButtonComponent }) => {
      renderComponent(ButtonComponent, {
        injector,
        hostFeatures: [LifecycleHooksFeature]
      });
    });
  }
}

If ButtonComponent uses other components app-foo, how should we declare it in @NgModule declarations?