Bug

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  tempValue: '',
  actions: {
    changeValue: function(value) {
      this.set('tempValue', '123');
      console.log('got', value);
      console.log('setting tempValue', this.get('tempValue'));
    }
  }
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
<input type="text" value={{tempValue}} oninput={{action "changeValue" value="target.value"}}>
<br>
{{tempValue}}
<br>

twiddle.json

{
  "version": "0.9.3",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.6.0",
    "ember-data": "2.6.1",
    "ember-template-compiler": "2.6.0"
  }
}