New Twiddle

components.inner-component.js

import Ember from 'ember';

export default Ember.Component.extend({
  log: Ember.computed(() => []),
  
  open() {
    this.get('log').pushObject('opened!');
  },
  
 	didInsertElement() {
    if (this.didInsertCallback) {
      this.sendAction('didInsertCallback', this);
    }
  },
  
  willDestroyElement() {
    if (this.willDestroyCallback) {
      this.sendAction('willDestroyCallback', this);
    }
  }
});

components.wrap-component.js

import Ember from 'ember';

export default Ember.Component.extend({
  
  click() {
    this._child.open();
  },
  
  actions: {
    didInsertCallback(child) {
      this._child = child;
    },
    willDestroyCallback(child) {
      this._child = null;
    }
  }
  
});

controllers.application.js

import Ember from 'ember';

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

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
{{wrap-component}}
<br>
<br>

templates.components.inner-component.hbs

{{#each log as |line|}}
  <p>{{line}}</p>
{{/each}}

templates.components.wrap-component.hbs

<h3>Great wrapped content</h3>
{{inner-component didInsertCallback="didInsertCallback" willDestroyCallback="willDestroyCallback"}}

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"
  }
}