faster minidom, drop polyfills.

tests/minidom/registerDomGlobals.ts

@@ -52,22 +52,14 @@ export function registerDomGlobals(
   assignGlobal(globals, 'Node', win.Node)
   assignGlobal(globals, 'Element', win.Element)
   assignGlobal(globals, 'HTMLElement', win.HTMLElement)
-  assignGlobal(
-    globals,
-    'HTMLSlotElement',
-    (document as Document).createElement('slot').constructor,
-  )
+  assignGlobal(globals, 'HTMLSlotElement', win.HTMLSlotElement)
   assignGlobal(globals, 'DocumentFragment', win.DocumentFragment)
   assignGlobal(globals, 'CustomEvent', win.CustomEvent)
   assignGlobal(globals, 'Event', win.Event)
   assignGlobal(globals, 'MouseEvent', win.MouseEvent)
-  assignGlobal(globals, 'Comment', createCommentConstructor(document))
+  assignGlobal(globals, 'Comment', win.Comment)
   assignGlobal(globals, 'Text', win.Text)
-  assignGlobal(
-    globals,
-    'HTMLTemplateElement',
-    (document as Document).createElement('template').constructor,
-  )
+  assignGlobal(globals, 'HTMLTemplateElement', win.HTMLTemplateElement)
 
   const windowCss = win.CSS as { escape?: unknown } | undefined
   assignGlobal(
@@ -107,13 +99,3 @@ export function ensureDomGlobals(): () => void {
   const { document, window } = parseHtml('<html><body></body></html>')
   return registerDomGlobals(window, document)
 }
-
-function createCommentConstructor(document: unknown): typeof Comment {
-  const doc = document as Document
-  const prototype = Object.getPrototypeOf(doc.createComment(''))
-  const CommentShim = function Comment(this: Comment, data?: string) {
-    return doc.createComment(data ?? '')
-  } as unknown as typeof Comment
-  CommentShim.prototype = prototype
-  return CommentShim
-}

tests/setup.ts

@@ -1,3 +1,31 @@
+import { afterAll, afterEach, beforeEach } from 'vitest'
+
 import { ensureDomGlobals } from './minidom/registerDomGlobals'
 
-ensureDomGlobals()
+const restoreDomGlobals = ensureDomGlobals()
+
+function resetDomState() {
+  const doc = globalThis.document as
+    | (Document & { head?: ParentNode | null; body?: ParentNode | null })
+    | undefined
+  doc?.head?.replaceChildren()
+  doc?.body?.replaceChildren()
+  if ('localStorage' in globalThis) {
+    ;(globalThis.localStorage as Storage).clear()
+  }
+  if ('sessionStorage' in globalThis) {
+    ;(globalThis.sessionStorage as Storage).clear()
+  }
+}
+
+beforeEach(() => {
+  resetDomState()
+})
+
+afterEach(() => {
+  resetDomState()
+})
+
+afterAll(() => {
+  restoreDomGlobals()
+})