New Twiddle

controllers.application.js

import Ember from 'ember';

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

controllers.foo.js

import Ember from 'ember';

export default Ember.Controller.extend({
  queryParams: ['foo'],
  
  foo: '',

  actions: {
    
  }
});

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('foo');
});

export default Router;

routes.foo.js

import Route from '@ember/routing/route';

export default Route.extend({

  queryParams: {
    foo: {refreshModel: true}
  },

  actions: {
    willTransition(transition) {
      transition.abort();
    }
  }
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
{{#link-to 'foo' (query-params foo='foo') }}Foo with foo{{/link-to}}
{{#link-to 'foo' (query-params foo='Bar') }}Foo with bar{{/link-to}}

{{outlet}}
<br>
<br>

templates.foo.hbs

<h1>Hi {{foo}}</h1>

<button {{action (mut foo) 'baz'}}>Set to Baz</button>

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"
  }
}