Create Ember app inside ShadowRoot node

index.js

class MyApp extends HTMLElement {
  constructor() {
    super();
    this.shadow = this.attachShadow({ mode: 'open' });
    this.shadow.classList = {
      contains: () => { return false }
    };
  }
  connectedCallback() {
    const node = document.createElement('div');
    this.shadow.appendChild(node);
    createEmberApp(node);
  }

}

customElements.define('my-app', MyApp);