Async Get Example

controllers.application\.js

import Controller from '@ember/controller';
import { task, timeout } from 'ember-concurrency';
import { cached } from 'tracked-toolbox';
import { tracked } from '@glimmer/tracking';

export default class ApplicationController extends Controller {
  @tracked haveFetchSucceed = true;

  @cached
  get appName() {
    this.fetchAppName.perform(this.haveFetchSucceed);
    return this.fetchAppName.last;
  }

  // I would have used a decorator from ember-concurrency-decorators, but that addon isn't working with Ember Twiddle.
  @(task(function * (haveFetchSucceed) {
    yield timeout(1000);
    if (!haveFetchSucceed) {
      throw new Error('Can\'t fetch app name')
    }
    return 'Async Get Example';
  }).drop())
  fetchAppName;
}

templates.application\.hbs

<h1>
{{#if this.appName.isRunning}}
  Loading
{{else if this.appName.isError}}
  Could not fetch app name
{{else}}
  Welcome to {{this.appName.value}}
{{/if}}
</h1>
<div>
  <button type="button" {{on "click" (fn (mut this.haveFetchSucceed) false)}}>
    Trigger error
  </button>
  <button type="button" {{on "click" (fn (mut this.haveFetchSucceed) true)}}>
    Trigger success
  </button>
</div>

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",
    "tracked-toolbox": "1.2.1",
    "ember-concurrency": "1.3.0"
  }
}