Computed Prop (get/set)

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'get/set Demo',
  model: null,
  
  valueOne: 'Hello',
  
  valueTwo: Ember.computed('valueOne', function() {
    return this.get('valueOne') + ' from two';
  }),
  
  valueThree: Ember.computed('valueOne', {
    get() {
      return this.get('valueOne');
    },
    set(p, v) {
      return v;
    }
  })
});

templates.application.hbs

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

<p>
	Value 2 is originally a computed value of Value 1.
</p>
<p>
  However, if you manually <strong>set</strong> Value 2, it will no longer act as a computed value of Value 1.
</p>
<p>
	If you need to manually set a <strong>comptued</strong> value, you a <strong>getter</strong> and <strong>setter</strong> as seen with Value 3.
</p>
<br>
<br>
Value 1: 
{{input value=valueOne}}
<br>
<br>
Value 2: 
{{input value=valueTwo}}
<br>
<br>
Value 3: 
{{input value=valueThree}}

twiddle.json

{
  "version": "0.14.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.js",
    "ember": "2.18.2",
    "ember-template-compiler": "2.18.2",
    "ember-testing": "2.18.2"
  },
  "addons": {
    "ember-data": "2.18.2"
  }
}