example to use each-in

controllers.application\.js

import Controller from '@ember/controller';

class ApplicationController extends Controller {
	abvalues = [
    {a:{title:"First A"},b:{title:"First B"}},
    {a:{title:"Second A"},b:{title:"Second B"}},
  ] 
}

export default ApplicationController;

templates.application\.hbs

{{#each this.abvalues as |abvalue|}}
  <div>
    {{#each-in abvalue as |key value|}}
      <strong>{{value.title}}</strong>
    {{/each-in}}
  </div>
{{/each}}

twiddle\.json

{
  "version": "0.16.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.js",
    "ember": "3.14.3",
    "ember-template-compiler": "3.14.3",
    "ember-testing": "3.14.3"
  },
  "addons": {
    "ember-data": "3.14.1"
  }
}