web-header-change-01.js

import { LitElement, html } from 'lit';
import { proxy } from 'comlink';
import { state } from '../../worker/index.js';

export class Component extends LitElement {
  // ... constructor

  async connectedCallback () {
    super.connectedCallback();

    state.subscribe('username', 'setLoggedIn', proxy(this._boundSetLoggedIn));
  }

  disconnectedCallback () {
    if (super.disconnectedCallback) super.disconnectedCallback();
    state.unsubscribe('username', 'setLoggedIn');
  }

  // ... setLoggedIn
}

window.customElements.define('web-header', Component);