A trailing whitespace riddle

components.external-link.js

import Ember from 'ember';

export default Ember.Component.extend({
  tagName: '',
  
	rel: Ember.computed('newTab', function() {
    return this.newTab ? 'noopener noreferrer' : null;
  }),

  target: Ember.computed('newTab', function() {
    return this.newTab ? '_blank' : '';
  })
});

controllers.application.js

import Ember from 'ember';

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

styles.app.css

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

.external-link--inline-block {
  display: inline-block;
}

.external-link--flush {
  margin-right: -4px;
}

templates.application.hbs

<h1>Welcome to {{appName}}</h1>

<h2>Angle brackets</h2>

<p>This is an
	<ExternalLink
    @href="https://www.example.com"
    @newTab={{true}}
  >
  	example link that opens a new tab
  </ExternalLink>.
</p>

<p>This is an
	<ExternalLink
  	@class="external-link--inline-block"
    @href="https://www.example.com"
    @newTab={{true}}
  >
  	inlined external link
  </ExternalLink>.
</p>

<p>This is
	<ExternalLink
  	@class="external-link--inline-block external-link--flush"
    @href="https://www.example.com"
    @newTab={{true}}
  >
    straight flush
  </ExternalLink>.
</p>

<p>All on <ExternalLink @href="https://www.example.com" @newTab={{true}}>one line</ExternalLink>.</p>

<h2>Curly braces</h2>

<p>This is an
	{{#external-link
    href="https://www.example.com"
    newTab=true
  }}example link that opens a new tab{{~/external-link~}}.
</p>

<p>This is an
	{{#external-link
  	class="external-link--inline-block"
    href="https://www.example.com"
    newTab=true
  }}
  	inlined external link
  {{/external-link}}.
</p>

<p>All on	{{#external-link href="https://www.example.com" newTab=true}}one line{{/external-link}}.</p>

templates.components.external-link.hbs

<a
  class="external-link {{@class}}"
  href={{@href}}
  rel={{rel}}
  target={{target}}
  tabindex="0"
>
  {{~yield~}}
</a>

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": {
  }
}