@pluginarch/create-parch/templates/app/src/pages/App.mjs

this is way to create a ui project

const HTMLElement = globalThis.HTMLElement || class {};
const customElements = globalThis.customElements || class {
  static define=(a,b)=>{}
};
class App extends BaseElement {
    constructor() {
      super();
      this.attachShadow({ mode: 'open' });
      this.shadowRoot.innerHTML = '<p>Hello, Welcome App!</p>';
    }

    connectedCallback() {
      console.log('AppElement is connected to the DOM');
    }
  }