New Twiddle

components.my-component.js

import Ember from 'ember';

export default Ember.Component.extend({
  _privateProp: 1,
  
  prop: Ember.computed({
    get() {
      return this._privateProp;
    },
    // Every time "prop" is set
    // Also update the emberObjectInstance
    set(key, value) {
      this._privateProp = value;
      this.set('emberObjectInstance.property', value);
      return value;
    }
  }),
  init() {
    this._super(...arguments);
    
    this.set('emberObjectInstance', Ember.Object.create({
      property: this.get('prop')
    }));
  },
  
  actions: {
    incrementProp() {
      this.set('prop', this.get('prop') + 1);
    },
  }
    
});

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle'
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
{{my-component}}
<br>
<br>

templates.components.my-component.hbs

You have clicked this button {{emberObjectInstance.property}} times.

<button {{action "incrementProp"}}>Click</button>

twiddle.json

{
  "version": "0.15.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.js",
    "ember": "3.4.3",
    "ember-template-compiler": "3.4.3",
    "ember-testing": "3.4.3"
  },
  "addons": {
    "ember-data": "3.4.2"
  }
}