active-title-no-deps

controllers.application.js

import Ember from 'ember';

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

mixins.active-title.js

import Ember from 'ember';

export default Ember.Mixin.create({
  activate() {
  	let app = Ember.getOwner(this).lookup('controller:application');
    app.set('currentPageTitle', this.get('title'));
    this._super(...arguments);
  },
  
  deactivate() {
    let app = Ember.getOwner(this).lookup('controller:application');
    app.set('currentPageTitle', null);
    this._super(...arguments);
  }
});

router.js

import Ember from 'ember';
import config from './config/environment';

const Router = Ember.Router.extend({
  location: 'none',
  rootURL: config.rootURL
});



Router.map(function() {
  this.route('inventory');
  this.route('finance');
});

export default Router;

routes.finance.js

import Ember from 'ember';
import ActiveTitleMixin from '../mixins/active-title';

export default Ember.Route.extend(ActiveTitleMixin, {
  title: 'Finance',
  
  activate() {
    this._super(...arguments);
  }
});

routes.inventory.js

import Ember from 'ember';
import ActiveTitleMixin from '../mixins/active-title';

export default Ember.Route.extend(ActiveTitleMixin, {
  title: 'Inventory'
});

templates.application.hbs

<h1>Header {{currentPageTitle}}</h1>
<br>

<br>
{{outlet}}
<br>
<br>

{{link-to 'Inventory' 'inventory'}}
{{link-to 'Finance' 'finance'}}

{{link-to 'Home' 'index'}}

templates.finance.hbs

HEllo finance

templates.inventory.hbs

Hello inventory

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": "2.12.0",
    "ember-template-compiler": "2.12.0",
    "ember-testing": "2.12.0"
  },
  "addons": {
    "ember-data": "2.12.1"
  }
}