New Twiddle

components.child-component.js

import Ember from 'ember';

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

components.parent-component.js

import Ember from 'ember';

export default Ember.Component.extend({
  actions: {
    doStuffWithItem (item) {
      alert(item.name);
    },
  }
});

controllers.application.js

import Ember from 'ember';

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

routes.application.js

import Ember from 'ember';

export default Ember.Route.extend({
  model() {
    return {items: [{ name: 'one' }, { name: 'two' }] };
  }
});

templates.application.hbs

{{parent-component model=model}}

templates.components.child-component.hbs

Items:
{{#each model.items as |item|}}
   <button onclick={{action itemClick item}}>
   	{{item.name}}
   </button>
{{/each}}

templates.components.parent-component.hbs

{{child-component model=model itemClick=(action "doStuffWithItem")}}

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"
  }
}