New Twiddle

components.my-component.js

import Ember from 'ember';

export default Ember.Component.extend({
  tagName: '',
  init() {
    this._super(...arguments);
    if (this.shouldError) {
      throw new Error("lol");
    }
  }
});

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  shouldError: false,
  shouldShow: false,
  actions: {
    toggleError: function() {
      this.toggleProperty("shouldError");
    },
    toggleShow: function() {
      this.toggleProperty("shouldShow");
    }
  }
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
Should Error: {{#if shouldError}}YES{{else}}NO{{/if}}
<button {{action "toggleError"}}>toggle</button>
<br>
Should Show: {{#if shouldShow}}YES{{else}}NO{{/if}}
<button {{action "toggleShow"}}>toggle</button>
<br>
<br>
<div>BEFORE {{#if shouldShow}}<MyComponent @shouldError={{shouldError}} />{{/if}} AFTER</div>
<br>

templates.components.my-component.hbs

SHOWING

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"
  }
}