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components.x-component.js

import Ember from 'ember';

export default Ember.Component.extend({
  tagName: '',
  
  init() {
    this.set('tagName', '');
    this._super(...arguments);
  },
  
  didInsertElement() {
    this._super(...arguments);
		console.log('X: ', this.element);
  },
});

components.y-component.js

import Ember from 'ember';

export default Ember.Component.extend({
  didInsertElement() {
    this._super(...arguments);
		console.log('Y: ', this.element);
  },
});

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  componentTagName: 'p',
  
  actions: {
   onClick() {
     console.log('Clicked', this.get('componentTagName'));
     
    	this.get('componentTagName') === 'p' ? this.set('componentTagName', 'h1') : this.set('componentTagName', 'p') 
   }
  }
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
{{outlet}}
<br>
<br>
{{#x-component tagName="p"}}x component{{/x-component}}
{{#y-component}}y component{{/y-component}}
{{#x-component tagName=componentTagName}}x component{{/x-component}}

<button {{action "onClick"}}>Click me</button>

templates.components.x-component.hbs

<div class="x">{{yield}}</div>

templates.components.y-component.hbs

{{yield}}

twiddle.json

{
  "version": "0.12.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.12.0",
    "ember-template-compiler": "2.12.0",
    "ember-testing": "2.12.0"
  },
  "addons": {
    "ember-data": "2.12.1"
  }
}