Errors

controllers.application.js

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

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  number: 0,
  computedProperty: computed('number', function() {
    if (this.number > 5) {
      throw new Error("Oh shit!")
    } else {
      return "You are on number " + this.number;                          
    }
  }),
  actions: {
    changeNumber() {
      this.incrementProperty('number');
    }
  }
});

templates.application.hbs

{{computedProperty}}

<button {{action "changeNumber"}}>Increment</button>

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"
  }
}