ui.module.ts

@NgModule({
  imports: [BrowserModule],
  declarations: [GreetingComponent],
  entryComponents: [GreetingComponent],
  bootstrap: []
})
export class UiModule {
  constructor(private injector: Injector) {}
  ngDoBootstrap() {
    const element = createCustomElement(GreetingComponent, { injector: this.injector });
    customElements.define('happynrwl-greeting', element); 
  }
}