Query Param Preservation

controllers.application\.js

import Controller from '@ember/controller';

export default class ApplicationController extends Controller {
  appName = 'Ember Twiddle';
   
  queryParams = ['foo', 'bar'];

  
}

controllers.index\.js

import Controller from '@ember/controller';
import { action } from '@ember/object';

export default Controller.extend({
  @action
  goToNewRoute(){
    const queryParams = {
      bar: 'BAR'
    };
    this.transitionToRoute('new-route', {queryParams});
  }
});

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('new-route');
});

export default Router;

routes.index\.js

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

export default Route.extend({
});

routes.new-route\.js

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

export default Route.extend({
  beforeModel(transition){
    this._super(...arguments);
    console.log(transition.to.queryParams);
    console.log(transition.from.queryParams);
  }
});

templates.application\.hbs

Foo param: {{this.foo}}
<br>
{{outlet}}
<br>
<br>

templates.index\.hbs

<button {{on "click" this.goToNewRoute}}>Go to New Route</button>

templates.new-route\.hbs

Welcome to the new route

twiddle\.json

{
  "version": "0.17.1",
  "EmberENV": {
    "FEATURES": {},
    "_TEMPLATE_ONLY_GLIMMER_COMPONENTS": false,
    "_APPLICATION_TEMPLATE_WRAPPER": true,
    "_JQUERY_INTEGRATION": true
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.5.1/jquery.js",
    "ember": "3.17.3",
    "ember-template-compiler": "3.17.3",
    "ember-testing": "3.17.3"
  },
  "addons": {
    "@glimmer/component": "1.0.0"
  }
}