fix: regression of issue: ShadowHost can't be a string (issue 941)

packages/rrweb/src/record/mutation.ts

@@ -27,6 +27,7 @@ import {
   isSerializedIframe,
   isSerializedStylesheet,
   inDom,
+  getShadowHost,
 } from '../utils';
 
 type DoubleLinkedListNode = {
@@ -268,18 +269,11 @@ export default class MutationBuffer {
       return nextId;
     };
     const pushAdd = (n: Node) => {
-      let shadowHost: Element | null = null;
-      if (
-        n.getRootNode?.()?.nodeType === Node.DOCUMENT_FRAGMENT_NODE &&
-        (n.getRootNode() as ShadowRoot).host
-      )
-        shadowHost = (n.getRootNode() as ShadowRoot).host;
-
       if (!n.parentNode || !inDom(n)) {
         return;
       }
       const parentId = isShadowRoot(n.parentNode)
-        ? this.mirror.getId(shadowHost)
+        ? this.mirror.getId(getShadowHost(n))
         : this.mirror.getId(n.parentNode);
       const nextId = getNextId(n);
       if (parentId === -1 || nextId === -1) {

packages/rrweb/src/utils.ts

@@ -519,16 +519,29 @@ export class StyleSheetMirror {
   }
 }
 
-export function getRootShadowHost(n: Node): Node | null {
-  const shadowHost = (n.getRootNode() as ShadowRoot).host;
-  // If n is in a nested shadow dom.
-  let rootShadowHost = shadowHost;
-
-  while (
-    rootShadowHost?.getRootNode?.()?.nodeType === Node.DOCUMENT_FRAGMENT_NODE &&
-    (rootShadowHost.getRootNode() as ShadowRoot).host
+/**
+ * Get the direct shadow host of a node in shadow dom. Returns null if it is not in a shadow dom.
+ */
+export function getShadowHost(n: Node): Element | null {
+  let shadowHost: Element | null = null;
+  if (
+    n.getRootNode?.()?.nodeType === Node.DOCUMENT_FRAGMENT_NODE &&
+    (n.getRootNode() as ShadowRoot).host
   )
-    rootShadowHost = (rootShadowHost.getRootNode() as ShadowRoot).host;
+    shadowHost = (n.getRootNode() as ShadowRoot).host;
+  return shadowHost;
+}
+
+/**
+ * Get the root shadow host of a node in nested shadow doms. Returns the node itself if it is not in a shadow dom.
+ */
+export function getRootShadowHost(n: Node): Node {
+  let rootShadowHost: Node = n;
+
+  let shadowHost: Element | null;
+  // If n is in a nested shadow dom.
+  while ((shadowHost = getShadowHost(rootShadowHost)))
+    rootShadowHost = shadowHost;
 
   return rootShadowHost;
 }
@@ -537,7 +550,7 @@ export function shadowHostInDom(n: Node): boolean {
   const doc = n.ownerDocument;
   if (!doc) return false;
   const shadowHost = getRootShadowHost(n);
-  return Boolean(shadowHost && doc.contains(shadowHost));
+  return doc.contains(shadowHost);
 }
 
 export function inDom(n: Node): boolean {

packages/rrweb/test/util.test.ts

@@ -1,7 +1,13 @@
 /**
  * @jest-environment jsdom
  */
-import { StyleSheetMirror } from '../src/utils';
+import {
+  getRootShadowHost,
+  StyleSheetMirror,
+  inDom,
+  shadowHostInDom,
+  getShadowHost,
+} from '../src/utils';
 
 describe('Utilities for other modules', () => {
   describe('StyleSheetMirror', () => {
@@ -75,4 +81,66 @@ describe('Utilities for other modules', () => {
       expect(mirror.add(new CSSStyleSheet())).toBe(1);
     });
   });
+
+  describe('inDom()', () => {
+    it('should get correct result given nested shadow doms', () => {
+      const shadowHost = document.createElement('div');
+      const shadowRoot = shadowHost.attachShadow({ mode: 'open' });
+      const shadowHost2 = document.createElement('div');
+      const shadowRoot2 = shadowHost2.attachShadow({ mode: 'open' });
+      const div = document.createElement('div');
+      shadowRoot.appendChild(shadowHost2);
+      shadowRoot2.appendChild(div);
+      // Not in Dom yet.
+      expect(getShadowHost(div)).toBe(shadowHost2);
+      expect(getRootShadowHost(div)).toBe(shadowHost);
+      expect(shadowHostInDom(div)).toBeFalsy();
+      expect(inDom(div)).toBeFalsy();
+
+      // Added to the Dom.
+      document.body.appendChild(shadowHost);
+      expect(getShadowHost(div)).toBe(shadowHost2);
+      expect(getRootShadowHost(div)).toBe(shadowHost);
+      expect(shadowHostInDom(div)).toBeTruthy();
+      expect(inDom(div)).toBeTruthy();
+    });
+
+    it('should get correct result given a normal node', () => {
+      const div = document.createElement('div');
+      // Not in Dom yet.
+      expect(getShadowHost(div)).toBeNull();
+      expect(getRootShadowHost(div)).toBe(div);
+      expect(shadowHostInDom(div)).toBeFalsy();
+      expect(inDom(div)).toBeFalsy();
+
+      // Added to the Dom.
+      document.body.appendChild(div);
+      expect(getShadowHost(div)).toBeNull();
+      expect(getRootShadowHost(div)).toBe(div);
+      expect(shadowHostInDom(div)).toBeTruthy();
+      expect(inDom(div)).toBeTruthy();
+    });
+
+    /**
+     * Given the textNode of a detached HTMLAnchorElement, getRootNode() will return the anchor element itself and its host property is a string.
+     * This corner case may cause an error in getRootShadowHost().
+     */
+    it('should get correct result given the textNode of a detached HTMLAnchorElement', () => {
+      const a = document.createElement('a');
+      a.href = 'example.com';
+      a.textContent = 'something';
+      // Not in Dom yet.
+      expect(getShadowHost(a.childNodes[0])).toBeNull();
+      expect(getRootShadowHost(a.childNodes[0])).toBe(a.childNodes[0]);
+      expect(shadowHostInDom(a.childNodes[0])).toBeFalsy();
+      expect(inDom(a.childNodes[0])).toBeFalsy();
+
+      // Added to the Dom.
+      document.body.appendChild(a);
+      expect(getShadowHost(a.childNodes[0])).toBeNull();
+      expect(getRootShadowHost(a.childNodes[0])).toBe(a.childNodes[0]);
+      expect(shadowHostInDom(a.childNodes[0])).toBeTruthy();
+      expect(inDom(a.childNodes[0])).toBeTruthy();
+    });
+  });
 });