New Twiddle

controllers.application.js

import Ember from 'ember';
import { inject as service } from '@ember/service';
import { task } from 'ember-concurrency';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  store: service(),
  
  runTask: task(function*() {
    this.set('taskResult', '');
    let model = this.store.createRecord('my-model');

    try {
      this.set('taskResult', yield model.task.perform());
    } catch (e) {
      this.set('taskResult', `ERROR: ${e.toString()}`);
    }    
  })
});

models.my-model.js

import Model from 'ember-data/model';
import { task } from 'ember-concurrency';

export default Model.extend({
  task: task(function*() {
    return yield 'task result';
  })
});

templates.application.hbs

<button onclick={{action 'runTask'}}>Run task</button>
<br>
Task result: {{taskResult}}

twiddle.json

{
  "version": "0.15.0",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.js",
    "ember": "3.2.2",
    "ember-concurrency": "*",
    "ember-template-compiler": "3.2.2",
    "ember-testing": "3.2.2"
  },
  "addons": {
    "ember-data": "canary"
  }
}