deep nested arrays test

controllers.application.js

import Ember from 'ember';
import { computed } from '@ember/object';
let idx = 0;

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
 
  foo: computed('bar.@each.baz.[]', function() {
    return this.bar.mapBy('baz').reduce((a, b) => a.concat(b));
  }),
  
  init() {
    this._super(...arguments);
    this.set('bar', [
      { baz: ['a', 'b', 'c'] },
      { baz: ['a', 'b', 'c'] },
      { baz: ['a', 'b', 'c'] }
    ]);
  },
  
  actions: {
    add() {
      this.bar[1].baz.push(idx++);
    }
  }
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
{{#each foo as |x|}}
  {{x}}, 
{{/each}}
<br>
<button {{action "add"}}>add</button>
<br>

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"
  }
}