Ember playground

controllers.application\.js

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

let Person = EmberObject.extend({
  // these will be supplied by `create`
  firstName: null,
  lastName: null,
  
  address: {
    road: 'Northland',
  },

  fullName: computed('firstName', 'lastName', function() {
    let firstName = this.get('firstName'),
        lastName  = this.get('lastName');

    return `${firstName} ${lastName}`;
  })
});


export default class ApplicationController extends Controller {
  tom = Person.create({
    firstName: 'Tom',
    lastName: 'Dale'
  })
    
  @computed('tom.{fullName,address.road}')
	get appName() {
    return this.tom.fullName + this.tom.address.road
  }

	@action
	changeAddress() {
    this.tom.set('address.road', Date.now());
  }
}

templates.application\.hbs

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

<button type="button" {{on "click" this.changeAddress}}>Change address</button>

<br>
<br>
{{outlet}}
<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"
  }
}