New Twiddle

controllers.application.js

import Ember from 'ember';
import { computed } from '@ember/object';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  init(){
    this._super(...arguments);
    this.first = "Mista";
    this.last = "Henry";
    this.name = 'Not MistaHenry';
  },
  first: null,
  last: null,
  name: computed('first', 'last', {
    get: function() {
      return this.get('first') + ' ' + this.get('last');
    },
    set: function(key, value) {
      var [ first, last ] = value.split(' ');

      this.set('first', first);
      this.set('last', last);
    }
  })
});

templates.application.hbs

{{name}}

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"
  }
}