New Twiddle

controllers.application\.js

import Controller from '@ember/controller';
import { action } from '@ember/object';

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

  @action
  onSelect(index) {
    this.selectedIndex = index;
  }
}

templates.application\.hbs

<h1>Welcome to {{this.appName}}</h1>
<br>
<br>
{{#if this.thingyType}}
{{component (concat "io-create-forms/" this.thingyType) class="flex-grow" model=this.model completeAction=(fn this.backToSelect)}}
{{else}}
{{#each this.thingyList as |thingy index|}}
        <Button @class={{concat "flex-grow" " io-pick-btn-" index}} @disabled={{thingy.disabled}} @title={{if-inplace io.disabledText}} @onClick={{fn this.onSelect index}}>
          {{t thingy.label}}
        </Button>
{{/each}}
{{/if}}
<br>
<br>

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"
  }
}