Handlebars nth

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  m: ['a', 'b', 'c', 'd', 'e', 'f']
});

templates.application.hbs

{{#each m as |item index|}}
	<div>
    {{item}}

    {{#if (eq (mod index 2) 0)}}
      !
    {{/if}}
  </div>
{{/each}}

twiddle.json

{
  "version": "0.13.0",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.16.2",
    "ember-template-compiler": "2.16.2",
    "ember-testing": "2.16.2"
  },
  "addons": {
    "ember-data": "2.16.3",
    "ember-math-helpers": "2.4.0",
    "ember-truth-helpers": "2.0.0"
  }
}