ember-awesome-macros#423

controllers.application.js

import Ember from 'ember';

import { groupBy } from 'ember-awesome-macros/array';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  
  postsGroupedByAuthor: groupBy('model', 'postsGroupedBy'),
  postsGroupedBy: 'author'
});

models.post.js

import Model from "ember-data/model";
import attr from "ember-data/attr";
import { belongsTo, hasMany } from "ember-data/relationships";

export default Model.extend({
  author: attr('string'),
  title: attr('string')
});

routes.application.js

import Ember from 'ember';

const { A } = Ember;

export default Ember.Route.extend({
  model() {
    let store = this.get('store');
    return A([
      store.createRecord('post', {
        author: 'max',
        title: 'post by max'
      }),
      store.createRecord('post', {
        author: 'max',
        title: 'another post by max'
      }),
      store.createRecord('post', {
        author: 'maria',
        title: 'post by maria'
      })
    ]);
  }
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
{{#each postsGroupedByAuthor as |postGroup|}}
	<h1>Author: {{postGroup.value}}</h1>
  
{{/each}}

twiddle.json

{
  "version": "0.13.0",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.16.2",
    "ember-template-compiler": "2.16.2",
    "ember-testing": "2.16.2"
  },
  "addons": {
  	"ember-awesome-macros": "0.41.0",
    "ember-data": "2.16.3"
  }
}