pyuan

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

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

	options = ['foo', 'bar', 'foobar'];
	
	@tracked

pyuan

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

export default class ApplicationController extends Controller {
  appName = 'Ember Twiddle';
	
	@tracked
	isFoo = false;
	

pyuan

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

class Foo {
  @tracked count = 0;

	reset() {
   this.count = 0; 
  }

pyuan

import Component from '@glimmer/component';

export default class extends Component {
  get foo() {
   return 'foo'; 
  }
}

pyuan

import Controller from '@ember/controller';

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

pyuan

import Controller from '@ember/controller';

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

pyuan

<h1>Foo</h1>
<h2>Bar</h2>

pyuan

import Controller from '@ember/controller';
import { computed, get, set } from '@ember/object';

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

	@(computed('appName'))
  get foo() {
    return get(this, 'appName');
  }

pyuan

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Eager/Lazy query collections',
});

pyuan

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  text: 'some text',
  count: Ember.computed('text', function() {
  	return this.get('text').length;
  }),
});