fix: clone iframe nodes better

src/clone-node.ts

@@ -1,6 +1,6 @@
 import type { Options } from './types'
 import { clonePseudoElements } from './clone-pseudos'
-import { createImage, toArray } from './util'
+import { createImage, toArray, isInstanceOfElement } from './util'
 import { getMimeType } from './mimes'
 import { resourceToDataURL } from './dataurl'
 
@@ -49,15 +49,15 @@ async function cloneSingleNode<T extends HTMLElement>(
   node: T,
   options: Options,
 ): Promise<HTMLElement> {
-  if (node instanceof HTMLCanvasElement) {
+  if (isInstanceOfElement(node, HTMLCanvasElement)) {
     return cloneCanvasElement(node)
   }
 
-  if (node instanceof HTMLVideoElement) {
+  if (isInstanceOfElement(node, HTMLVideoElement)) {
     return cloneVideoElement(node, options)
   }
 
-  if (node instanceof HTMLIFrameElement) {
+  if (isInstanceOfElement(node, HTMLIFrameElement)) {
     return cloneIFrameElement(node)
   }
 
@@ -72,12 +72,23 @@ async function cloneChildren<T extends HTMLElement>(
   clonedNode: T,
   options: Options,
 ): Promise<T> {
-  const children =
-    isSlotElement(nativeNode) && nativeNode.assignedNodes
-      ? toArray<T>(nativeNode.assignedNodes())
-      : toArray<T>((nativeNode.shadowRoot ?? nativeNode).childNodes)
+  let children: T[] = []
+
+  if (isSlotElement(nativeNode) && nativeNode.assignedNodes) {
+    children = toArray<T>(nativeNode.assignedNodes())
+  } else if (
+    isInstanceOfElement(nativeNode, HTMLIFrameElement) &&
+    nativeNode.contentDocument?.body
+  ) {
+    children = toArray<T>(nativeNode.contentDocument.body.childNodes)
+  } else {
+    children = toArray<T>((nativeNode.shadowRoot ?? nativeNode).childNodes)
+  }
 
-  if (children.length === 0 || nativeNode instanceof HTMLVideoElement) {
+  if (
+    children.length === 0 ||
+    isInstanceOfElement(nativeNode, HTMLVideoElement)
+  ) {
     return clonedNode
   }
 
@@ -114,9 +125,19 @@ function cloneCSSStyle<T extends HTMLElement>(nativeNode: T, clonedNode: T) {
           Math.floor(parseFloat(value.substring(0, value.length - 2))) - 0.1
         value = `${reducedFont}px`
       }
+
+      if (
+        isInstanceOfElement(nativeNode, HTMLIFrameElement) &&
+        name === 'display' &&
+        value === 'inline'
+      ) {
+        value = 'block'
+      }
+
       if (name === 'd' && clonedNode.getAttribute('d')) {
         value = `path(${clonedNode.getAttribute('d')})`
       }
+
       targetStyle.setProperty(
         name,
         value,
@@ -127,17 +148,17 @@ function cloneCSSStyle<T extends HTMLElement>(nativeNode: T, clonedNode: T) {
 }
 
 function cloneInputValue<T extends HTMLElement>(nativeNode: T, clonedNode: T) {
-  if (nativeNode instanceof HTMLTextAreaElement) {
+  if (isInstanceOfElement(nativeNode, HTMLTextAreaElement)) {
     clonedNode.innerHTML = nativeNode.value
   }
 
-  if (nativeNode instanceof HTMLInputElement) {
+  if (isInstanceOfElement(nativeNode, HTMLInputElement)) {
     clonedNode.setAttribute('value', nativeNode.value)
   }
 }
 
 function cloneSelectValue<T extends HTMLElement>(nativeNode: T, clonedNode: T) {
-  if (nativeNode instanceof HTMLSelectElement) {
+  if (isInstanceOfElement(nativeNode, HTMLSelectElement)) {
     const clonedSelect = clonedNode as any as HTMLSelectElement
     const selectedOption = Array.from(clonedSelect.children).find(
       (child) => nativeNode.value === child.getAttribute('value'),
@@ -150,7 +171,7 @@ function cloneSelectValue<T extends HTMLElement>(nativeNode: T, clonedNode: T) {
 }
 
 function decorate<T extends HTMLElement>(nativeNode: T, clonedNode: T): T {
-  if (clonedNode instanceof Element) {
+  if (isInstanceOfElement(clonedNode, Element)) {
     cloneCSSStyle(nativeNode, clonedNode)
     clonePseudoElements(nativeNode, clonedNode)
     cloneInputValue(nativeNode, clonedNode)

src/embed-images.ts

@@ -1,6 +1,6 @@
 import { Options } from './types'
 import { embedResources } from './embed-resources'
-import { toArray } from './util'
+import { toArray, isInstanceOfElement } from './util'
 import { isDataUrl, resourceToDataURL } from './dataurl'
 import { getMimeType } from './mimes'
 
@@ -38,20 +38,19 @@ async function embedImageNode<T extends HTMLElement | SVGImageElement>(
   clonedNode: T,
   options: Options,
 ) {
+  const isImageElement = isInstanceOfElement(clonedNode, HTMLImageElement)
+
   if (
-    !(clonedNode instanceof HTMLImageElement && !isDataUrl(clonedNode.src)) &&
+    !(isImageElement && !isDataUrl(clonedNode.src)) &&
     !(
-      clonedNode instanceof SVGImageElement &&
+      isInstanceOfElement(clonedNode, SVGImageElement) &&
       !isDataUrl(clonedNode.href.baseVal)
     )
   ) {
     return
   }
 
-  const url =
-    clonedNode instanceof HTMLImageElement
-      ? clonedNode.src
-      : clonedNode.href.baseVal
+  const url = isImageElement ? clonedNode.src : clonedNode.href.baseVal
 
   const dataURL = await resourceToDataURL(url, getMimeType(url), options)
   await new Promise((resolve, reject) => {
@@ -67,7 +66,7 @@ async function embedImageNode<T extends HTMLElement | SVGImageElement>(
       image.loading = 'eager'
     }
 
-    if (clonedNode instanceof HTMLImageElement) {
+    if (isImageElement) {
       clonedNode.srcset = ''
       clonedNode.src = dataURL
     } else {
@@ -89,7 +88,7 @@ export async function embedImages<T extends HTMLElement>(
   clonedNode: T,
   options: Options,
 ) {
-  if (clonedNode instanceof Element) {
+  if (isInstanceOfElement(clonedNode, Element)) {
     await embedBackground(clonedNode, options)
     await embedImageNode(clonedNode, options)
     await embedChildren(clonedNode, options)

src/util.ts

@@ -222,3 +222,21 @@ export async function nodeToDataURL(
   foreignObject.appendChild(node)
   return svgToDataURL(svg)
 }
+
+export const isInstanceOfElement = <
+  T extends typeof Element | typeof HTMLElement | typeof SVGImageElement,
+>(
+  node: Element | HTMLElement | SVGImageElement,
+  instance: T,
+): node is T['prototype'] => {
+  if (node instanceof instance) return true
+
+  const nodePrototype = Object.getPrototypeOf(node)
+
+  if (nodePrototype === null) return false
+
+  return (
+    nodePrototype.constructor.name === instance.name ||
+    isInstanceOfElement(nodePrototype, instance)
+  )
+}