New Twiddle

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  artists: [
    category:[{
      'name': 'abc',
      'id': 1
    }, {
      'name': 'abcde',
      'id': 2
    }, {
      'name': 'abcdefg',
      'id': 3
    }]
  ]
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
{{outlet}}
<br>
<br>
{{#each-in (group-by "name" artists) as |name artists|}}
  <h3>{{name}}</h3>
  <ul>
    {{#each artists as |artist|}}
      <li>{{artist.name}}</li>
    {{/each}}
  </ul>
{{/each-in}}

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",
    "ember-composable-helpers": "2.2.0"
  }
}