empty htmlSafe truthiness

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  htmlSafeEmpty: Ember.String.htmlSafe(''),
  stringEmpty: '',
  arrayEmpty: []
});

templates.application.hbs

htmlSafeEmpty: {{if htmlSafeEmpty 'true' 'false'}}
<br>
stringEmpty: {{if stringEmpty 'true' 'false'}}
<br>
arrayEmpty: {{if arrayEmpty 'true' 'false'}}

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"
  }
}