Action w/o quotes

components.my-component.js

import Ember from 'ember';

export default Ember.Component.extend({
  actionA() {
    console.log('component function handler');
  },
  
  actions: {
    actionA() {
     console.log('component action handler'); 
    }
  }
  
});

components.my-sub-component.js

import Ember from 'ember';

export default Ember.Component.extend({
  
  actions: {
   click() {
     console.log('sub-component action handler');
   }
  }
  
});

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  emberVersion: Ember.VERSION,
  appName: 'Actions w/o quotes',
  actionA() {
		console.log('controller function handler'); 
   },
  actions: {
   actionA() {
		console.log('controller action handler'); 
   }
  }
});

templates.application.hbs

<h1>{{appName}}</h1>
Ember: <strong>{{emberVersion}}</strong>
<pre>\{{my-component}}</pre>
{{my-component}}

templates.components.my-component.hbs

<p>Action with quotes and with <code>action</code>
<pre>\{{my-sub-component click=(action "actionA")}}</pre>
{{my-sub-component click=(action "actionA")}}</p>
<hr />
<p>Action with quotes and without <code>action</code>
<pre>\{{my-sub-component click="actionA"}}</pre>
{{my-sub-component click="actionA"}}</p>
<hr />
<p>Action without quotes and with <code>action</code>
<pre>\{{my-sub-component click=(action actionA)}}</pre> 
{{my-sub-component click=(action actionA)}}</p>
<hr />
<p>Action without quotes and without <code>action</code>
<pre>\{{my-sub-component click=actionA}}</pre> 
{{my-sub-component click=actionA}}</p>

templates.components.my-sub-component.hbs

<button {{action "click"}}>Press me</button>

twiddle.json

{
  "version": "0.10.5",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.8.0",
    "ember-data": "2.8.0",
    "ember-template-compiler": "2.8.0",
    "ember-testing": "2.8.0"
  },
  "addons": {}
}