@each nest test

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  food: [
		Ember.Object.create({
      name: 'taco',
      reviews: [Ember.Object.create({
        rating: 5
      })]
		}),
		Ember.Object.create({
      name: 'burrito',
      reviews: [Ember.Object.create({
        rating: 4
      })]
		})
	],
  lowestRating: Ember.computed('[email protected][email protected]', function() {
    return this.get('food').map(function(food) {
      console.log('DID UPDATE')
      return Math.min(food.get('reviews').mapBy('rating'));
    }).sort().reverse().pop();
  }),
  actions: {
    changeRating: function() {
      this.get('food.firstObject.reviews.firstObject').setProperties({ rating: 3 });
    }
  }
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
<button {{action 'changeRating'}}>ChangeRating</button>
{{lowestRating}}
{{outlet}}
<br>
<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"
  }
}