New Twiddle

components.my-component.js

import Ember from 'ember';

export default Ember.Component.extend({
  actions: {
    activate() {
      this.get('didActivate')();
    }
  }
});

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  actions: {
    activate() {
      document.getElementById('my-input').focus();
    }
  }
});

templates.application.hbs

{{#my-component didActivate=(action "activate")}}
	<input id="my-input" />
{{/my-component}}

templates.components.my-component.hbs

<button {{action "activate"}}>Activate</button>
{{yield}}

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"
  }
}