angular-custom-element-output.ts

 connectedCallback(): void {
   // subscribe to event emitters of Angular Component and dispatch Custom
   // Events
   const eventEmitters = this.componentFactory.outputs.map(propName => this.componentRef.instance as any)[propName]);
   this.outputEvents = merge(...eventEmitters);   
   this.ngElementEventsSubscription = this.outputEvents.subscribe(e => {
     const customEvent = document.createEvent('CustomEvent');
     customEvent.initCustomEvent(e.name, false, false, e.value);
     element.dispatchEvent(customEvent);
   });
 }