New Twiddle

components.my-component.js

import Ember from 'ember';
import { alias } from '@ember/object/computed';

export default Ember.Component.extend({
  numbers: alias('data.numbers'),
  
 	click() {
    this.data.numbers.replace(0, 1, [Math.ceil(Math.random() * 10)]);
  	//this.numbers.pushObject(Math.random() * 10);
	}
});

controllers.application.js

import Ember from 'ember';
import { A } from '@ember/array';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  data: { numbers: A([10]) }
});

templates.application.hbs

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

templates.components.my-component.hbs

{{#each numbers as |num|}}
	<li>{{num}}</li>
{{/each}}

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"
  }
}