Computed Setter

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  
  param1: 'hello world',
  
  myProp: Ember.computed('param1', {
		get() {
      console.log('jcdean called me!');
  		return this.get('param1');
		},
		// set(key, value) {
		// 	return value;
		// },
 	}),
  
  actions: {
  	updateMyProp() {
      alert(this.get('myProp'));
    	this.set('myProp', 'blahblahblah');
      alert(this.get('myProp'));
      this.set('param1', 'goodbye');
      alert(this.get('myProp'));
    }
  }
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
{{outlet}}
<button {{action "updateMyProp"}}>Click</button>
<br>
<br>

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"
  }
}