LinkTo Active Styling

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
});

controllers.my-bar-route.js

import Ember from 'ember';

import { BARS } from 'twiddle/routes/my-bar-route/my-bar-child-route';

export default Ember.Controller.extend({
  bars: null,
  
  init() {
    this._super(...arguments);
    this.setProperties({ bars: BARS });
  }
});

controllers.my-bar-route.my-bar-child-route.js

import Ember from 'ember';

import { timestamps } from 'twiddle/routes/my-bar-route/my-bar-child-route';

export default Ember.Controller.extend({
  timestamps: null,
  
  afterModelBeforeModelDiff: Ember.computed(
    'timestamps.afterModel', 
    'timestamps.beforeModel', 
    function() {
      return (
        this.get('timestamps.afterModel') - 
        this.get('timestamps.beforeModel')
      );
    }
  ),
  
  init() {
    this._super(...arguments);
    this.set('timestamps', timestamps);
  }
});

router.js

import EmberRouter from '@ember/routing/router';
import config from './config/environment';

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

Router.map(function() {
  this.route('my-foo-route');
  this.route('my-bar-route', function() {
    this.route('my-bar-child-route', { path: ':bar_id' });
  });
  this.route('my-foo-related-route');
});

export default Router;

routes.my-bar-route.js

import Ember from 'ember';

export default Ember.Route.extend({
});

routes.my-bar-route.my-bar-child-route.js

import Ember from 'ember';

const BAR1 = { id: 'bar-1', name: 'Bar 1' };
const BAR2 = { id: 'bar-2', name: 'Bar 2' };
export const BARS = [BAR1, BAR2];

export const timestamps = {};

export default Ember.Route.extend({
  beforeModel(model) {
    Ember.set(timestamps, 'beforeModel', Date.now());
    return new Ember.RSVP.Promise((resolve) => {
      Ember.run.later(resolve, 100);
    });
  },
  
  model(params) {
    const id = params.bar_id;
    return new Ember.RSVP.Promise((resolve) => {
      const bar = BARS.findBy('id', id);
      Ember.run.later(() => resolve(bar), 100);
    });
  },
  
  afterModel(model) {
    Ember.set(timestamps, 'afterModel', Date.now());
  }
});

routes.my-foo-related-route.js

import Ember from 'ember';

export default Ember.Route.extend({
});

routes.my-foo-route.js

import Ember from 'ember';

export default Ember.Route.extend({
});

styles.app.css

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

a {
  text-decoration: none;
  color: gray;
}

a.active {
  color: dodgerblue;
}

templates.application.hbs

<code>Ember link-to .active styling</code>

<p>
	{{link-to "Go to Foo" "my-foo-route" 
    class="NavItem" 
    current-when="my-foo-route my-foo-related-route"
  }}
</p>

<p>
  {{link-to "Go to Bar" "my-bar-route" class="NavItem"}}
</p>

{{outlet}}

templates.my-bar-route.hbs

This is the BAR route

{{#each bars as |bar|}}
  <p>
    {{link-to 
      bar.name 
      "my-bar-route.my-bar-child-route" 
      bar
     }}
     (model)
     
    <span>---</span>
    
    {{link-to bar.name 
    	"my-bar-route.my-bar-child-route" 
      bar.id
    }}
    (model.id)
  </p>
{{/each}}

{{outlet}}

templates.my-bar-route.my-bar-child-route.hbs

<p>
	I am the route for {{model.name}}
</p>

<p>
  <code>beforeModel</code> ran at {{timestamps.beforeModel}}
</p>

<p>
  <code>afterModel</code> ran at {{timestamps.afterModel}}
</p>

<p>
  <code>afterModel</code> - <code>beforeModel</code> {{afterModelBeforeModelDiff}}
</p>

templates.my-foo-related-route.hbs

I am a route related to FOO

templates.my-foo-route.hbs

This is the FOO route

<p>
	{{link-to "Go to Foo-Related Page" "my-foo-related-route"}}
</p>

{{outlet}}

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": "2.12.2"
  }
}