New Twiddle

components.blurring-item.js

import Ember from 'ember';

function log(string) {
  let node = $('<p>').text(`${string} (input? ${$('input').length > 0})`);
  node.appendTo('body');
}

export default Ember.Component.extend({
  tagName: 'input',
  willRender() {
    log('willRender');
  },
  willDestroyElement() {
    log('willDestroyElement');
  },
  focusOut() {
    log('focusOut');
  },
  didRender() {
    log('didRender');
  }
});

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  isItemVisible: true,
  actions: {
    toggle(property) {
      if (this.get(property)) {
        $('input')[0].focus();
      }
      this.toggleProperty(property);
    }
  }
});

templates.application.hbs

<h1>focusOut dispatch during teardown</h1>

<br>
Clicking the "Toggle Visibility" button will cause the input to be programmatically focused, and will set a property causing it to be removed from rendering.
<br><br>
In Ember 2.7, the `willDestroyElement` hook is called before the input is removed from the DOM.
<br><br>
In Ember 2.8, the `willDestroyElement` hook is called before the input is removed from the DOM. Then, the `focusOut` handler is called during `input` removal.
<br><br>

<!-- -------------------------- -->

<button {{action 'toggle' 'isItemVisible'}}>Toggle Visibility</button>
<br>
{{#if isItemVisible}}
  {{blurring-item}}
{{/if}}
<br>
<br>

twiddle.json

{
  "version": "0.12.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "release",
    "ember-template-compiler": "release",
    "ember-testing": "release",
    "ember-data": "1.13.15"
  }
}