How to pass data from Angular Component to plain html page

Question

I am using Angular web components in a static html page. I am able to inject data into Angular component. But when I try to retrieve data from Angular component to the HTML page, it is not working. I am not sure what I am doing wrong here.

The code is as below:

component ts code

  @Output() myOutput:EventEmitter<string>= new EventEmitter();

  outputMessage:string="I am child component."
  
  sendValues() {
    this.myOutput.emit(this.outputMessage);
  }

component html code

<button (click)="sendValues"> Send Data </button>

JS code in static html

   var commCompTag = document.getElementsByTagName('comm-comp');
   if(commCompTag.length > 0){
      console.log('>>>>>>>>>>>>>>>>>>>>>>>>>>');
      commCompTag[0].addEventListener('myoutput', (event) => {
         var evtDetails = event;
         console.log('evtDetails >>> ', evtDetails);
         console.log(event.detail);
      });
      // commCompTag[0].addEventListener('myoutput', function(event) {
      //   var evtDetails1 = event;

      //   console.log('evtDetails1 >>> ', evtDetails1);
      //   console.log(event.originalEvent.detail);
      // });
   }

I have tried the above solution by referring to Angular Elements EventEmmitter : $event not showing emitted value but it didn't help me out. So it will be great if someone can give me some pointers to resolve this issue.

https://stackblitz.com/edit/angular-ivy-vnrj8a

Answer 1

Because the index.html is technically not part of the bootstrapped angular app, you may need to resort to non Angular-specific solutions.

One approach/POC may be to do the following.

Get a reference to my-app element via constructor

constructor(private elRef: ElementRef) {}

construct and dispatch an event on the nativeElement

sendValues() {
    console.log('sending values');
    this.myOutput.emit(this.outputMessage);
    const event = new CustomEvent('my-app-data', {
      detail: {
        value: {
          message: this.outputMessage
        }
      }
    });
    this.elRef.nativeElement.dispatchEvent(event);
  }

Register to listen for that event in index.html

jsonCommCompTag[0].addEventListener('my-app-data', function(event) {
      var evtDetails1 = event;

      console.log('evtDetails1 >>> ', evtDetails1.detail.value.message);
    });

don't forget invocation in your button click event handler in app.component.html

(click)="sendValues()"

STACKBLITZ

https://stackblitz.com/edit/angular-ivy-zbj7ru?file=src/index.html