Content Container

application.controller.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  
  contentContainer: [],
  
  actions: {
  	newElement: function() {
       this.get('contentContainer').pushObject({
          id: Math.floor(Math.random() * 100000)
       });
    },
    
    removeElement: function(element) {
     this.get('contentContainer').removeObject(element);
    }
  }
});

application.template.hbs

<h1>Welcome to {{appName}}</h1>
<br>

<button {{action 'newElement'}}>
    	Click for new element 		
 </button> 
    
    
<br>

  {{#each contentContainer as |element|}}
    {{#fade-element}}
     		<span class="fade-in">
       			{{element.id}} 
       		<button {{action 'removeElement' element}}> 
        		x 
       		</button>
       			<br> 
     		</span>
     {{/fade-element}}
  {{/each}}
    

fade-element.component.js

import Ember from 'ember';

export default Ember.Component.extend({
  
  willDestroyElement : function () {
      var clone = this.$().clone();
    	clone.children().removeClass('fade-in');
      var prev = this.$().prev();
      Ember.run.scheduleOnce('afterRender', () => {
          prev.after(clone);
          clone.fadeOut();
      });  
  },
});

fade-element.template.hbs

{{yield}}

router.js

import Ember from 'ember';
import config from './config/environment';

const Router = Ember.Router.extend({
  location: 'none'
});

Router.map(function() {
});

export default Router;

styles.app.css

body {
  margin: 12px 16px;
  font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
  font-size: 12pt;
}

.fade-in{
  animation: fadeIn 1s;
}



@keyframes fadeIn {
    from {
        background-color: yellow;
        opacity:0;
    }
    to {
        background-color: white;
        opacity:1;
    }
}

twiddle.json

{
  "version": "0.6.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "https://cdnjs.cloudflare.com/ajax/libs/ember.js/2.3.1/ember.debug.js",
    "ember-data": "https://cdnjs.cloudflare.com/ajax/libs/ember-data.js/2.3.3/ember-data.js",
    "ember-template-compiler": "https://cdnjs.cloudflare.com/ajax/libs/ember.js/2.2.0/ember-template-compiler.js"
  }
}