params test

components.my-component\.js

import Component from '@glimmer/component';
import { action } from '@ember/object';

export default class extends Component {
  @action
  changeParam(number, event) {
    const params = this.args.param.slice(0);
    
    if (event.target.checked) {
      params.pushObject(number);
    } else {
      params.removeObject(number);
    }
    
    this.args.updateParam(params.uniq());
  }
}

controllers.application\.js

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

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

	param = [];

	@action
	updateParam(number) {
    set(this, 'param', number)
  }
}

routes.application\.js

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

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

templates.application\.hbs

<h1>Welcome to {{this.appName}}</h1>
<MyComponent @param={{this.param}} @updateParam={{this.updateParam}} />
<br>
<br>
{{outlet}}
<br>
<br>

templates.components.my-component\.hbs

Number of params: {{@param.length}}
<br />
<label><Input type="checkbox" {{on "change" (fn this.changeParam 1) }} />Change param to [1]</label>
<label><Input type="checkbox" {{on "change" (fn this.changeParam 2) }} />Change param to [1,2]</label>

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"
  }
}