clicks

controllers.application\.js

import Controller from '@ember/controller';

export default class ApplicationController extends Controller {
  clicked(message, stopPropagation, event) {
    alert(message);
    
    if (stopPropagation) {
      event.stopPropagation();
    }
  }
}

templates.application\.hbs

<div onclick={{fn this.clicked 'outer'}} role="button">
  <button onclick={{fn this.clicked 'inner' true}}>
  	with stopPropagation
  </button>
  <br>
  <button onclick={{fn this.clicked 'inner' false}}>
  	without stopPropagation
  </button>
</div>

twiddle\.json

{
  "version": "0.17.1",
  "EmberENV": {
    "FEATURES": {},
    "_TEMPLATE_ONLY_GLIMMER_COMPONENTS": false,
    "_APPLICATION_TEMPLATE_WRAPPER": true,
    "_JQUERY_INTEGRATION": true
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.5.1/jquery.js",
    "ember": "3.18.1",
    "ember-template-compiler": "3.18.1",
    "ember-testing": "3.18.1"
  },
  "addons": {
    "@glimmer/component": "1.0.0"
  }
}