notifyPropertyChange

controllers.application\.js

import Controller from '@ember/controller';
import { computed } from '@ember/object';

let counter = 0;

export default Controller.extend({
  appName: 'Ember Twiddle',
  
  foo: 1,
	
  bar: computed('foo', function() {
    counter++;
    return this.get('foo') + counter + 1;
  }),
  
  actions: {
    notify() {
      this.notifyPropertyChange('foo');
    }
  }
})

templates.application\.hbs

<h1>Welcome to {{this.appName}}</h1>

<p>Tests if notifyPropertyChange will retrigger a computed property successfully</p>

{{this.bar}}

<button {{action "notify"}}>recalc</button>

<br>
<br>
{{outlet}}
<br>
<br>

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": "3.8.3",
    "ember-template-compiler": "3.8.3",
    "ember-testing": "3.8.3"
  }
}