Array Property

components.ui-test.js

import Ember from 'ember';

export default Ember.Component.extend({
  testArray: [],
  
  didInsertElement() {
    this._super(...arguments);
    const elementId = this.get('elementId')
    
    this.get('testArray').push(elementId)
  }
});

controllers.application.js

import Ember from 'ember';

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

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
{{ui-test}}

{{ui-test}}

templates.components.ui-test.hbs

<h2>Test {{elementId}}</h2>
{{#each testArray as |item index|}}
	{{test}}
{{/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": "2.5.1",
    "ember-template-compiler": "2.5.1",
  },
  "addons": {
  }
}