RSVP rejection window error

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember RSVP rejection demo',
  
  actions: {
    die() { 
    	Ember.RSVP.reject("blah blah")
    },
    swallow() { 
      Ember.RSVP.reject("blah blah").catch(() => {})
    }
  }
});

routes.application.js

import Ember from 'ember';

export default Ember.Route.extend({
  beforeModel() { 
    window
      .addEventListener('error', () => {
      	alert('Caught terrible error!')
    	});
  }
});

styles.app.css

body {
  margin: 12px 16px;
  font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
  font-size: 12pt;
}

templates.application.hbs

<div id="this-ember-app">
<h1>Welcome to {{appName}}</h1>
<br>
<br>
{{outlet}}

<p>
Here, we've setup the follow button to merely perform <strong>RSVP.reject("blah")</strong> in the controller without actually throwing, 
</p>
<p>however, due to the vagaries of how RSVP promises work, we'll see that it triggers the <strong>window.addEventListener("error", () => { ... }) </strong> that we've setup in the route's beforeModel
</p>

<button {{action "die" on="click"}}>
  Die
</button>

<p>
Interestingly enough, if we swallow the error, via <strong>RSVP.reject("blah").catch(() => {})</strong> we don't get the window error
</p>

<button {{action "swallow" on="click"}}>
  Swallow
</button>
<br>
<br>
</div>

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"
  }
}