New Twiddle

components.my-component.js

import Ember from 'ember';

export default Ember.Component.extend({
  resolvedWith: '',
  
  actions: {
    save() {
      let data = this.getProperties('firstName', 'lastName');
      this.get('onSave')(data)
        .then((resolvedWith) => {
          this.set('resolvedWith', resolvedWith);
      	});
      
      return false;
    }
  }
});

controllers.application.js

import Ember from 'ember';
import { Promise } from 'rsvp';

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

routes.application.js

import Ember from 'ember';

export default Ember.Route.extend({
  actions: {
    save(data) {
      return new Promise((resolve) => {
        resolve(
        	JSON.stringify(data)
        );
      });
    }
  }
});

templates.application.hbs

<h1>closure actions</h1>
{{my-component
  onSave=(route-action 'save')
}}

templates.components.my-component.hbs

<form onsubmit={{action 'save'}}>
  <label>first name</label> {{input value=firstName}}
  <label>last name</label> {{input value=lastName}}
  <input type="submit">
</form>
<p>Promise has resolved with:</p>
<pre>{{resolvedWith}}</pre>

twiddle.json

{
  "version": "0.15.0",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.js",
    "ember": "3.2.2",
    "ember-template-compiler": "3.2.2",
    "ember-testing": "3.2.2"
  },
  "addons": {
    "ember-data": "3.2.0",
    "ember-route-action-helper": "2.0.6"
  }
}