whatever.js

customElements.define("todo-list", class extends HTMLElement {
  constructor() {
    super();
    const root = this.attachShadow({mode: "open"});
    root.innerHTML = `
      <ul>
        ${store().map((todo, index) => `
          <li>
            <todo-item index=${index}>
              ${todo}
            </todo-item>
          </li>
        `).join("")}
      </ul>
    `;
  }
});