Route transition

controllers.foo.bar\.js

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

export default class extends Controller {
  @inject router;
  
  @action
  async goToFoo() {
    await this.router.transitionTo('foo', { queryParams: { q: 1 } });  
  }
}

controllers.foo\.js

import Controller from '@ember/controller';

export default Controller.extend({
});

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', function() {
    this.route('bar');
  });
});

export default Router;

routes.foo.bar\.js

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

export default Route.extend({
});

routes.foo\.js

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

export default class extends Route {
  queryParams = {
    q: {
      refreshModel: true
    }
  };

  model(params) {
    return params.q;
  }
}

templates.application\.hbs

<LinkTo @route="foo">foo</LinkTo> |
<LinkTo @route="foo.bar">foo.bar</LinkTo>

<br><br>

{{outlet}}

templates.foo.bar\.hbs

bar

<br><br>

<button type="button" {{on "click" this.goToFoo}}>
  Go to foo
</button>

templates.foo\.hbs

foo (q: {{@model}})

<br><br>



<br><br>

<br>

{{outlet}}

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"
  }
}