auto-bind

auto-bind.js

import { action } from '@ember-decorators/object';

export default class AutoBind {
  end = false;
  
  constructor() {
    window.addEventListener('beforeunload', this.onDestroy);
  }

  @action
  onDestroy(event) {
    this.end = true;
    console.log(this.end);
    event.preventDefault();
    event.returnValue = false;
  }
}

controllers.application.js

import Ember from 'ember';
import AutoBind from 'twiddle/auto-bind';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  init() {
    this._super();
    const autoBind = new AutoBind();
  }
});

templates.application.hbs

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

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": "latest",
    "ember-template-compiler": "latest",
    "ember-testing": "3.4.3"
  },
  "addons": {
    "ember-decorators": "latest"
  }
}