Passing back helper

components.my-component.js

import Ember from 'ember';

export default Ember.Component.extend({
});

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle'
});

helpers.example-helper.js

import Ember from 'ember';
import { htmlSafe } from '@ember/template';

export function exampleHelper(params/*, hash*/) {
  return htmlSafe('Inside helper:' + params);
}

export default Ember.Helper.helper(exampleHelper);

templates.application.hbs

<h1>Example of component providing helper (Not possible externally)</h1>
<br>
{{#my-component as |api|}}
  {{api.coolHelper}}
{{/my-component}}

templates.components.my-component.hbs

<div style="background-color: red; padding: 20px;">
  Component
  <br>
  {{yield (hash
    coolHelper=(example-helper '123')
  )}}
</div>

twiddle.json

{
  "version": "0.15.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.js",
    "ember": "3.4.3",
    "ember-template-compiler": "3.4.3",
    "ember-testing": "3.4.3"
  },
  "addons": {
    "ember-data": "3.4.2"
  }
}