New Twiddle

components.my-component\.js

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

export default Component.extend({
  init(...args) {
        this._super(...args);
        if (!this.currentDate) set(this, 'currentDate', '2000-12-12');
      },
    
      currentDate: null,
    
      actions: {
        updateCurrentDate(val) {
          const currentDate = val;
          this.callbackAction(currentDate);
        },
      },
})

controllers.application\.js

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

export default Controller.extend({
  currentDate: '1900-01-01',
  
  actions: {
    changeControllerDateTime() {
      set(this, 'currentDate', 'x');
    },
    submitAction(date, time) {
      set(this, 'currentDate', date);
    }
  }
})

templates.application\.hbs

<h1>Welcome to {{this.appName}}</h1>
<br>
<br>
controller date time: {{currentDate}}
<button onclick={{action "changeControllerDateTime"}}>change controller datetime</button>
{{my-component currentDate=currentDate callbackAction=(action "submitAction")}}
<br>
<br>

templates.components.my-component\.hbs

component date time: {{currentDate}}

<input value={{currentDate}} oninput={{action "updateCurrentDate" value="target.value"}}>

twiddle\.json

{
  "version": "0.17.0",
  "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/3.3.1/jquery.js",
    "ember": "3.12.2",
    "ember-template-compiler": "3.12.2",
    "ember-testing": "3.12.2"
  },
  "addons": {
    "@glimmer/component": "1.0.0"
  }
}