New Twiddle

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle'
});

models.my-model.js

import Model from 'ember-data/model';
import attr from 'ember-data/attr';
import { belongsTo, hasMany } from 'ember-data/relationships';
import { observer } from '@ember/object';

export default Model.extend({
  justAnAttribute: attr("string"),
  
  doSomethingWhenCurrentStateChanges: observer("currentState", function() {
    console.log("currentState changed!");
  })
});

routes.application.js

import Ember from 'ember';

export default Ember.Route.extend({
  model() {
    const model = this.store.pushPayload({
      "data": [{
        "type": "my-model",
        "id": "1",
        "attributes": {
          "justAnAttribute": "Hello world"
        }
      ]
    });
    return model;
		return this.store.createRecord("my-model", {
      justAnAttribute: "hello world"
    });
  }
});

templates.application.hbs

<h1>Welcome to {{model.justAnAttribute}}</h1>
<br>
<br>
{{outlet}}
<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"
  }
}