Chaining promises

controllers.application.js

import Ember from 'ember';

const wait = (time) => new Promise(resolve => setTimeout(resolve, time));

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  
  actions: {
   	foo() {
      this.set('firstResolved', false);
      this.set('secondResolved', false);
		  this.set('finalResolved', false);
      return wait(2000).then(() => {
        this.set('firstResolved', true);
       	wait(2000).then(() => {
        	this.set('secondResolved', true);
        });
      }).then(() => {
				this.set('finalResolved', true);
      });
    },
    
    bar() {
      this.set('firstResolved', false);
      this.set('secondResolved', false);
		  this.set('finalResolved', false);
      return wait(2000).then(() => {
        this.set('firstResolved', true);
       	return wait(2000).then(() => {
        	this.set('secondResolved', true);
        });
      }).then(() => {
				this.set('finalResolved', true);
      });
    }
  }
});

styles.app.css

body {
  margin: 12px 16px;
  font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
  font-size: 12pt;
}

.row {
  margin: 10px;
  padding: 10px;
  border-radius: 10px;
  border: 1px solid;
  text-align: center;
}

.row:after {
  content: ' ' 
}

.green {
  background-color: hsl(120, 50%, 50%);
}

button {
 	padding: 20px; 
}

templates.application.hbs

<h1>Example of promise chaining</h1>
<br>
<br>
<div class="row {{if firstResolved 'green'}}">First Promise</div>
<div class="row {{if secondResolved 'green'}}">Second Promise</div>
<div class="row {{if finalResolved 'green'}}">Chained</div>
<br>
<br>
<button {{action 'foo'}}>Unchained</button>
<button {{action 'bar'}}>Chained</button>

twiddle.json

{
  "version": "0.15.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.js",
    "ember": "3.4.3",
    "ember-template-compiler": "3.4.3",
    "ember-testing": "3.4.3"
  },
  "addons": {
    "ember-data": "3.4.2"
  }
}