New Twiddle

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  result: null,
  actions: {
  	do() {
    
    	var hello = []
hello.push([])
hello.objectAt(0).push(1)
hello.objectAt(0).push(2)

hello.push([])
hello.objectAt(1).push(9)

this.set('result', JSON.stringify(hello.lastObject));
console.log(hello.lastObject)

    }
  }
});

templates.application.hbs

<button {{action 'do'}}>calc</button>
result: {{this.result}}

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"
  }
}