Hash vs Custom Context

controllers.application\.js

import Controller from '@ember/controller';

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

helpers.new-context\.js

import { helper } from '@ember/component/helper';

export default helper(function newContextHelper() {
  return {};
});

helpers.not\.js

import { helper } from '@ember/component/helper';

export default helper(function notHelper([ value ]) {
  return !value;
});

helpers.set\.js

import { helper } from '@ember/component/helper';

import { set } from '@ember/object';

export default helper(function setHelper(args0) {
  return (...args1) => {
      const [ ctx, key, val ]  = [ ...args0, ...args1 ];
      set(ctx, key, val);
      return val;
    };
});

templates.application\.hbs

{{#let (hash) as |hashCtx|}}
  <button {{on "click" (set hashCtx "toggle" (not hashCtx.toggle))}}>
    {{if (not hashCtx.toggle) "!"}} Hash Context
  </button>
{{/let}}
{{#let (new-context) as |newCtx|}}
  <button {{on "click" (set newCtx "toggle" (not newCtx.toggle))}}>
    {{if (not newCtx.toggle) "!"}} New Context
  </button>
{{/let}}
{{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",
    "ember-event-helpers": "^0.1.1"
  },
  "addons": {
    "@glimmer/component": "1.0.0"
  }
}