app.module.ts

import { Injector, NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { createCustomElement } from '@angular/elements';

import { AppComponent } from './app.component';

@NgModule({
  declarations: [
    AppComponent
  ],
  imports: [
    BrowserModule
  ],
  providers: [],
  // comment this and the selector in app.component in to make runnable standalone
  // bootstrap: [AppComponent]
  entryComponents: [
    AppComponent
  ]
})
export class AppModule {
  constructor(private injector: Injector) {}
  ngDoBootstrap(): void {
    const playerElement = createCustomElement(AppComponent, { injector: this.injector });
    customElements.define('player-aspect', playerElement);
  }
}