fix: shouldExcludeFromA11yTree runs in IE11

IE11 returns `undefined` for missing `parentElement`.

Author: briandipalma

src/__tests__/role-helpers.js

@@ -1,4 +1,9 @@
-import {getRoles, logRoles, getImplicitAriaRoles} from '../role-helpers'
+import {
+  getRoles,
+  logRoles,
+  getImplicitAriaRoles,
+  shouldExcludeFromA11yTree,
+} from '../role-helpers'
 import {render} from './helpers/test-utils'
 
 beforeEach(() => {
@@ -57,6 +62,10 @@ function setup() {
       <li data-testid='b-list-item-1'>Item 1</li>
       <li data-testid='b-list-item-2'>Item 2</li>
     </ul>
+
+    <svg data-testid='a-svg'>
+      <rect width="100" height="100" />
+    </svg>
    </article>
 </section>
   `)
@@ -89,6 +98,7 @@ function setup() {
     input: getByTestId('a-input-1'),
     input2: getByTestId('a-input-2'),
     textarea: getByTestId('a-textarea'),
+    svg: getByTestId('a-svg'),
   }
 }
 
@@ -160,4 +170,10 @@ test('getImplicitAriaRoles returns expected roles for various dom nodes', () =>
   expect(getImplicitAriaRoles(input)).toEqual(['textbox'])
 })
 
+test('shouldExcludeFromA11yTree handles SVGs', () => {
+  const {svg} = setup()
+
+  expect(shouldExcludeFromA11yTree(svg)).toEqual(false)
+})
+
 /* eslint no-console:0 */

src/role-helpers.js

@@ -26,7 +26,7 @@ function shouldExcludeFromA11yTree(element) {
   let visibility = computedStyle.visibility
 
   let currentElement = element
-  while (currentElement !== null) {
+  while (currentElement) {
     if (currentElement.hidden === true) {
       return true
     }