New Twiddle

controllers.application\.js

import Controller from '@ember/controller';

class UserCollection {
  constructor(users) {
    this.users = users;
  }

  [Symbol.iterator]() {
    let i = 0;
    let { users } = this;

    return {
      next() {
        if (i < users.length) {
          return { done: false, value: users[i++] };
        }

        return { done: true };
      },
    };
  }
}

export default class ApplicationController extends Controller {
  appName = 'Ember Twiddle';

  users = new UserCollection([
    { first: 'Chris', last: 'Thoburn' },
    { first: 'Tom', last: 'Dale' },
    { first: 'Yehuda', last: 'Katz' },
  ]);
}

templates.application\.hbs

<h1>Welcome to {{this.appName}}</h1>

<ul>
  {{#each this.users as |user index|}}
    <li>{{index}} - {{user.first}}</li>
  {{/each}}
</ul>

twiddle\.json

{
  "version": "0.17.1",
  "EmberENV": {
    "FEATURES": {},
    "_TEMPLATE_ONLY_GLIMMER_COMPONENTS": false,
    "_APPLICATION_TEMPLATE_WRAPPER": true,
    "_JQUERY_INTEGRATION": true
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.5.1/jquery.js",
    "ember": "3.18.1",
    "ember-template-compiler": "3.18.1",
    "ember-testing": "3.18.1"
  },
  "addons": {
    "@glimmer/component": "1.0.0"
  }
}