Route Only QP Example

controllers.application\.js

import Controller from '@ember/controller';
import { inject as service } from '@ember/service';

export default class ApplicationController extends Controller {
  appName = 'Ember Twiddle';

  transitionToQp = () => {
    this.router.transitionTo({ queryParams: { foo: 123 } });  
  }
  
  @service router;
}

routes.application\.js

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

export default Route.extend({
  queryParams: { foo: true }
});

templates.application\.hbs

<button {{on "click" this.transitionToQp}}>Test</button>
{{foo}}

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": "3.18.1",
    "ember-template-compiler": "3.18.1",
    "ember-testing": "3.18.1"
  },
  "addons": {
    "@glimmer/component": "1.0.0"
  }
}