text: import { HTMLElementExtended } from '@webformula/pax-core/index.js';
  
  customElements.define('mdw-expander-header', class extends HTMLElementExtended {
    constructor() {
      super();
      this.cloneTemplate();
    }
  
    connectedCallback() {
      this.parentNode.registerHeader(this);
    }
  
    registerArrow(arrow) {
      this.arrow = arrow;
    }
  
    open() {
      if (this.arrow) this.arrow.open();
    }
  
    close() {
      if (this.arrow) this.arrow.close();
    }
  
    template() {
      return /* html */`
        <slot></slot>
      `;
    }
  });
  