Email Conversation Test

controllers.application\.js

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

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  items: computed(function() {
    // return [1];
    // return [1,2];
    // return [1,2,3];
    // return [1,2,3,4];
    return [1,2,3,4,5];
  })
});

templates.application\.hbs

<h1>Email Conversation Test</h1>
<br>
<ul>
  	<li>sender-info-wrap {{if (gt items.length 1) 'first-child'}}--> {{items.firstObject}} </li>
	  
    {{#if (gt items.length 4)}}
    	<li>more-email-counter</li>
    {{/if}}
		
    {{#if (gt items.length 2)}}
    	<li>more-email-container Start {{if (gt items.length 4) 'Display:none'}}</li>
      {{#each items as |item index|}}
          {{#if (and index (not-eq index (sub items.length 1)))}}
            <li>sender-info-wrap {{item}}</li>
          {{/if}}
      {{/each}}
      <li>more-email-container End</li>
    {{/if}}
    
    {{#if (gte items.length 2)}}
      <li>sender-info-wrap last-child--> {{items.lastObject}} </li>
  	{{/if}}
</ul>
<br>

twiddle\.json

{
  "version": "0.15.0",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.js",
    "ember": "3.2.2",
    "ember-template-compiler": "3.2.2",
    "ember-testing": "3.2.2"
  },
  "addons": {
    "ember-data": "3.2.0",
    "ember-math-helpers": "2.7.0",
    "ember-truth-helpers": "2.1.0"
  }
}