parent child query params

controllers.application.js

import Ember from 'ember';

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

controllers.parent.child.js

import Ember from 'ember';

export default Ember.Controller.extend({
});

controllers.parent.child2.js

import Ember from 'ember';

export default Ember.Controller.extend({
  queryParams: ['mode', {
  	mode: {
      as: 'other'
    }
  }],
  other: null
});

controllers.parent.js

import Ember from 'ember';

export default Ember.Controller.extend({
  queryParams: ['mode'],
  mode: null
});

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');
    this.route('child2');
  });
});

export default Router;

routes.parent.child.js

import Ember from 'ember';

export default Ember.Route.extend({
});

routes.parent.child2.js

import Ember from 'ember';

export default Ember.Route.extend({
});

routes.parent.js

import Ember from 'ember';

export default Ember.Route.extend({
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
{{outlet}}
{{#link-to 'parent' (query-params mode="fun")}}parent{{/link-to}}
{{#link-to 'parent.child'}}child{{/link-to}}
{{#link-to 'parent.child2'}}child2{{/link-to}}
<br>
<br>

templates.parent.child.hbs

<h3>Child</h3>

templates.parent.child2.hbs

<h3>Child 2</h3>

<p>{{mode}}</p>

templates.parent.hbs

<h2>Parent</h2>

<p>{{mode}}</p>

{{outlet}}

twiddle.json

{
  "version": "0.15.0",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.js",
    "ember": "3.2.2",
    "ember-template-compiler": "3.2.2",
    "ember-testing": "3.2.2"
  },
  "addons": {
    "ember-data": "3.2.0"
  }
}