Remove `Element.closest` polyfill

Element.closest is natively supported [1] by our minimum browser targets.

[1] https://developer.mozilla.org/en-US/docs/Web/API/Element/closest#Browser_compatibility

src/annotator/guest.js

@@ -15,7 +15,6 @@ import {
 } from './highlighter';
 import * as rangeUtil from './range-util';
 import selections from './selections';
-import { closest } from '../shared/dom-element';
 import { normalizeURI } from './util/url';
 
 /**
@@ -666,8 +665,7 @@ export default class Guest extends Delegator {
    */
   isEventInAnnotator(event) {
     return (
-      closest(/** @type {Element} */ (event.target), '.annotator-frame') !==
-      null
+      /** @type {Element} */ (event.target).closest('.annotator-frame') !== null
     );
   }
 

src/annotator/highlighter.js

-import { closest } from '../shared/dom-element';
-
 const SVG_NAMESPACE = 'http://www.w3.org/2000/svg';
 
 function isCSSPropertySupported(property, value) {
@@ -35,7 +33,7 @@ function getPdfCanvas(highlightEl) {
   // It also assumes that the `highlightEl` element is somewhere under
   // the `.textLayer` div.
 
-  const pageEl = closest(highlightEl, '.page');
+  const pageEl = highlightEl.closest('.page');
   if (!pageEl) {
     return null;
   }
@@ -170,8 +168,7 @@ export function highlightRange(normedRange, cssClass = 'hypothesis-highlight') {
   // a PDF. These highlights should be invisible.
   const isPlaceholder =
     textNodes.length > 0 &&
-    closest(
-      /** @type {Element} */ (textNodes[0].parentNode),
+    /** @type {Element} */ (textNodes[0].parentNode).closest(
       '.annotator-placeholder'
     ) !== null;
 

src/shared/dom-element.js

-/**
- * Ponyfills [1] for DOM element methods that are not supported in all browsers.
- *
- * [1] https://github.com/sindresorhus/ponyfill
- */
-
-/**
- * Implementation of `element.closest(selector)`. This is used to support browsers
- * (IE 11) that don't have a native implementation.
- *
- * @param {Element|null} element
- * @param {string} selector
- */
-export function closest(element, selector) {
-  while (element) {
-    if (element.matches(selector)) {
-      return element;
-    }
-    element = element.parentElement;
-  }
-  return null;
-}

src/shared/test/dom-element-test.js

-import { closest } from '../dom-element';
-
-describe('shared/dom-element', () => {
-  let container;
-
-  beforeEach(() => {
-    container = document.createElement('div');
-    document.body.appendChild(container);
-  });
-
-  afterEach(() => {
-    container.remove();
-  });
-
-  describe('closest', () => {
-    it('returns closest matching ancestor', () => {
-      container.innerHTML = `
-<div class="outer">
-  <div class="middle">
-    <div class="inner"></div>
-  </div>
-</div>
-`;
-
-      const el = container.querySelector('.inner');
-      const target = container.querySelector('.outer');
-
-      assert.equal(closest(el, '.inner'), el);
-      assert.equal(closest(el, '.outer'), target);
-      assert.isNull(closest(el, '.no-match'));
-    });
-  });
-});

src/sidebar/components/thread-card.js

@@ -4,7 +4,6 @@ import { createElement } from 'preact';
 import { useCallback, useMemo } from 'preact/hooks';
 
 import propTypes from 'prop-types';
-import { closest } from '../../shared/dom-element';
 import useStore from '../store/use-store';
 import { withServices } from '../util/service-context';
 
@@ -50,9 +49,11 @@ function ThreadCard({ frameSync, settings, thread }) {
   /**
    * Is the target's event an <a> or <button> element, or does it have
    * either as an ancestor?
+   *
+   * @param {Element} target
    */
   const isFromButtonOrLink = target => {
-    return !!closest(target, 'button') || !!closest(target, 'a');
+    return !!target.closest('button') || !!target.closest('a');
   };
 
   return (
@@ -61,7 +62,7 @@ function ThreadCard({ frameSync, settings, thread }) {
       onClick={e => {
         // Prevent click events intended for another action from
         // triggering a page scroll.
-        if (!isFromButtonOrLink(e.target)) {
+        if (!isFromButtonOrLink(/** @type {Element} */ (e.target))) {
           scrollToAnnotation(threadTag);
         }
       }}