Actions send arguments up

components.podcast\.js

import Component from '@glimmer/component';
import { tracked } from '@glimmer/tracking';
import { action } from '@ember/object';

export default class extends Component {
  @tracked title = '';

  @action
  subscribe() {
    // Do some work here to get chart data like the date they clicked
    this.args.onSubscribe(this.args.title);
  }
}

controllers.application\.js

import Controller from '@ember/controller';

export default class ApplicationController extends Controller {
  appName = 'Ember Twiddle';
}

controllers.usage\.js

import Controller from '@ember/controller';
import { action } from '@ember/object';

export default class UsageController extends Controller {
  @action
  subscribeToPodcast(podcastTitle) {
    console.log('Subscribed to ' + podcastTitle);
	}
}

router\.js

import EmberRouter from '@ember/routing/router';
import config from './config/environment';

const Router = EmberRouter.extend({
  location: 'none',
  rootURL: config.rootURL
});

Router.map(function() {
  this.route('usage', { path: '/usage' });

});

export default Router;

routes.usage\.js

import Route from '@ember/routing/route';

export default Route.extend({
});

templates.application\.hbs

<h1>Welcome to {{this.appName}}</h1>
<br>
<LinkTo @route="usage">Usage</LinkTo>
<br>
{{outlet}}
<br>
<br>

templates.components.podcast\.hbs

<div>
	<p>{{@title}}</p>
  <button {{on "click" subscribe}}>Subscribe</button>
 </div>

templates.usage\.hbs

Hi
<Podcast @title="Maintainable" @onSubscribe={{this.subscribeToPodcast}} />
<Podcast @title="Javascript Jabber" />

twiddle\.json

{
  "version": "0.17.1",
  "EmberENV": {
    "FEATURES": {},
    "_TEMPLATE_ONLY_GLIMMER_COMPONENTS": false,
    "_APPLICATION_TEMPLATE_WRAPPER": true,
    "_JQUERY_INTEGRATION": true
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.5.1/jquery.js",
    "ember": "3.18.1",
    "ember-template-compiler": "3.18.1",
    "ember-testing": "3.18.1"
  },
  "addons": {
    "@glimmer/component": "1.0.0"
  }
}