Computed Update Count

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  
  fullName: '',
  
  firstName: Ember.computed('fullName', function() {
		return this.get('fullName').split(' ')[0];
  }),
  
  greeting: Ember.computed('firstName', function() {
    this.set('count', this.get('count')+1);
    return `Hello ${this.get('firstName')}`;
  }),
  
	count: 0,

});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
Fullname: <input value={{fullName}} oninput={{action (mut fullName) value='target.value'}}>
<br>
Firstname: {{firstName}}
<br>
Greeting: {{greeting}}
<br>
Count: {{count}}

twiddle.json

{
  "version": "0.10.6",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.9.0",
    "ember-data": "2.0.1",
    "ember-template-compiler": "2.9.0",
    "ember-testing": "2.9.0"
  },
  "addons": {}
}