router.transitionTo() Twiddle

controllers.application\.js

import Controller from '@ember/controller';

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

controllers.parent.child-route\.js

import Controller from '@ember/controller';

export default Controller.extend({
  queryParams: ['sickParam']
});

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('parent', function() {
    this.route('child-route');
  });
});

export default Router;

routes.application\.js

import Route from '@ember/routing/route';
import { inject as service } from '@ember/service';

export default Route.extend({
  router: service('router'),
  
  actions: {
    loadChild() {
      this.router.transitionTo('parent.child-route',  {
        queryParams: { sickParam: 'iller-value' },
      });
    }
  }
});

routes.parent.child-route\.js

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

export default Route.extend({
  model() {
    console.log('child route model hook loaded')
  }
});

routes.parent\.js

import Route from '@ember/routing/route';
import { inject as service } from '@ember/service';

export default Route.extend({
  router: service('router'),
  
  model() {
    console.log('parent route model hook')
  },
  actions: {
    loadChild() {
      this.router.transitionTo('parent.child-route',  {
        queryParams: { sickParam: 'iller-value' },
      });
    }
  }
});

templates.application\.hbs

<h1>Welcome to {{this.appName}}</h1>
<p>Check the console.logs: there is a console log in the model hook of the parent route and the child-route. Navigating to the child route via router.transitionTo() does not reload the parent route (the parent routes model() hook does not fire again)</p>
<br>
{{#link-to 'parent'}}link-to parent{{/link-to}}
{{!-- <button {{action "loadChild"}}>transitionTo() child</button><br> --}}
<br>
{{outlet}}
<br>
<br>

templates.parent.child-route\.hbs

Child Route Loaded
{{outlet}}

templates.parent\.hbs

Parent Route loaded<br>
{{!-- {{#link-to 'parent.child-route'}}link-to child{{/link-to}}<br> --}}
<button {{action "loadChild"}}>transitionTo() child</button><br>
{{outlet}}<br>

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"
  }
}