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                <!-- Web component polyfills for IE/Edge and Firefox < version 59 -->
<script src=""></script>

<!-- Creates error -->
<my-draggable create-shadow></my-draggable>

<!-- No error -->
<!-- <my-draggable></my-draggable> -->




import Draggable from "[email protected]/Draggable.js?module";


class MyDraggable extends HTMLElement {
  constructor() {
  // Called when the element is added to the DOM
  connectedCallback() {
    // create a shadow root if the element has a 'create-shadow' attribute
    if (!this.root) {
      if (this.hasAttribute("create-shadow")) {
        this.root = this.attachShadow({ mode : "open" });
      } else {
        this.root = this;
  firstRendered() {
    this.root.innerHTML = `
      <div class="draggable" style="width:100px;height:100px;background:dodgerblue"></div>
    // don't use the name 'draggable' because HTMLElement uses it 😮
    this.$draggable = new Draggable(this.root.querySelector(".draggable"), {
      allowContextMenu: true,
      // creates an error when declaring a bounds inside shadowRoot
      bounds: window

customElements.define("my-draggable", MyDraggable);