add checker for replayer to make it stable when data has duplicated n…

…odes

packages/rrweb-snapshot/src/rebuild.ts

@@ -8,7 +8,7 @@ import {
   attributes,
   legacyAttributes,
 } from './types';
-import { isElement, Mirror } from './utils';
+import { isElement, Mirror, isNodeMetaEqual } from './utils';
 
 const tagMap: tagMap = {
   script: 'noscript',
@@ -364,6 +364,19 @@ export function buildNodeWithSN(
     afterAppend,
     cache,
   } = options;
+  /**
+   * Add a check to see if the node is already in the mirror. If it is, we can skip the whole process.
+   * This situation (duplicated nodes) can happen when recorder has some unfixed bugs and the same node is recorded twice. Or something goes wrong when saving or transferring event data.
+   * Duplicated node creation may cause unexpected errors in replayer. This check tries best effort to prevent the errors.
+   */
+  if (mirror.has(n.id)) {
+    // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
+    const nodeInMirror = mirror.getNode(n.id)!;
+    // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
+    const meta = mirror.getMeta(nodeInMirror)!;
+    // For safety concern, check if the node in mirror is the same as the node we are trying to build
+    if (isNodeMetaEqual(meta, n)) return mirror.getNode(n.id);
+  }
   let node = buildNode(n, { doc, hackCss, cache });
   if (!node) {
     return null;

packages/rrweb-snapshot/src/utils.ts

@@ -5,6 +5,12 @@ import {
   nodeMetaMap,
   IMirror,
   serializedNodeWithId,
+  serializedNode,
+  NodeType,
+  documentNode,
+  documentTypeNode,
+  textNode,
+  elementNode,
 } from './types';
 
 export function isElement(n: Node): n is Element {
@@ -213,3 +219,30 @@ export function is2DCanvasBlank(canvas: HTMLCanvasElement): boolean {
   }
   return true;
 }
+
+export function isNodeMetaEqual(a: serializedNode, b: serializedNode): boolean {
+  if (!a || !b || a.type !== b.type) return false;
+  if (a.type === NodeType.Document)
+    return a.compatMode === (b as documentNode).compatMode;
+  else if (a.type === NodeType.DocumentType)
+    return (
+      a.name === (b as documentTypeNode).name &&
+      a.publicId === (b as documentTypeNode).publicId &&
+      a.systemId === (b as documentTypeNode).systemId
+    );
+  else if (
+    a.type === NodeType.Comment ||
+    a.type === NodeType.Text ||
+    a.type === NodeType.CDATA
+  )
+    return a.textContent === (b as textNode).textContent;
+  else if (a.type === NodeType.Element)
+    return (
+      a.tagName === (b as elementNode).tagName &&
+      JSON.stringify(a.attributes) ===
+        JSON.stringify((b as elementNode).attributes) &&
+      a.isSVG === (b as elementNode).isSVG &&
+      a.needBlock === (b as elementNode).needBlock
+    );
+  return false;
+}

packages/rrweb-snapshot/test/utils.test.ts

@@ -0,0 +1,150 @@
+/**
+ * @jest-environment jsdom
+ */
+import { NodeType, serializedNode } from '../src/types';
+import { isNodeMetaEqual } from '../src/utils';
+import { serializedNodeWithId } from 'rrweb-snapshot';
+
+describe('utils', () => {
+  describe('isNodeMetaEqual()', () => {
+    const document1: serializedNode = {
+      type: NodeType.Document,
+      compatMode: 'CSS1Compat',
+      childNodes: [],
+    };
+    const document2: serializedNode = {
+      type: NodeType.Document,
+      compatMode: 'BackCompat',
+      childNodes: [],
+    };
+    const documentType1: serializedNode = {
+      type: NodeType.DocumentType,
+      name: 'html',
+      publicId: '',
+      systemId: '',
+    };
+    const documentType2: serializedNode = {
+      type: NodeType.DocumentType,
+      name: 'html',
+      publicId: '',
+      systemId: 'http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd',
+    };
+    const text1: serializedNode = {
+      type: NodeType.Text,
+      textContent: 'Hello World',
+    };
+    const text2: serializedNode = {
+      type: NodeType.Text,
+      textContent: 'Hello world',
+    };
+    const comment1: serializedNode = {
+      type: NodeType.Comment,
+      textContent: 'Hello World',
+    };
+    const comment2: serializedNode = {
+      type: NodeType.Comment,
+      textContent: 'Hello world',
+    };
+    const element1: serializedNode = {
+      type: NodeType.Element,
+      tagName: 'div',
+      attributes: {
+        className: 'test',
+      },
+      childNodes: [],
+    };
+    const element2: serializedNode = {
+      type: NodeType.Element,
+      tagName: 'span',
+      attributes: {
+        'aria-label': 'Hello World',
+      },
+      childNodes: [],
+    };
+    const element3: serializedNode = {
+      type: NodeType.Element,
+      tagName: 'div',
+      attributes: { id: 'test' },
+      childNodes: [comment1 as serializedNodeWithId],
+    };
+
+    it('should return false if two nodes have different node types', () => {
+      expect(
+        isNodeMetaEqual(
+          (undefined as unknown) as serializedNode,
+          (null as unknown) as serializedNode,
+        ),
+      ).toBeFalsy();
+      expect(isNodeMetaEqual(document1, element1)).toBeFalsy();
+      expect(isNodeMetaEqual(document1, documentType1)).toBeFalsy();
+      expect(isNodeMetaEqual(documentType1, element1)).toBeFalsy();
+      expect(isNodeMetaEqual(text1, comment1)).toBeFalsy();
+      expect(isNodeMetaEqual(text1, element1)).toBeFalsy();
+      expect(isNodeMetaEqual(comment1, element1)).toBeFalsy();
+    });
+
+    it('should compare meta data of two document nodes', () => {
+      expect(
+        isNodeMetaEqual(document1, JSON.parse(JSON.stringify(document1))),
+      ).toBeTruthy();
+      expect(
+        isNodeMetaEqual(JSON.parse(JSON.stringify(document2)), document2),
+      ).toBeTruthy();
+      expect(isNodeMetaEqual(document1, document2)).toBeFalsy();
+    });
+
+    it('should compare meta data of two documentType nodes', () => {
+      expect(
+        isNodeMetaEqual(
+          documentType1,
+          JSON.parse(JSON.stringify(documentType1)),
+        ),
+      ).toBeTruthy();
+      expect(
+        isNodeMetaEqual(
+          JSON.parse(JSON.stringify(documentType2)),
+          documentType2,
+        ),
+      ).toBeTruthy();
+      expect(isNodeMetaEqual(documentType1, documentType2)).toBeFalsy();
+    });
+
+    it('should compare meta data of two text nodes', () => {
+      expect(
+        isNodeMetaEqual(text1, JSON.parse(JSON.stringify(text1))),
+      ).toBeTruthy();
+      expect(
+        isNodeMetaEqual(JSON.parse(JSON.stringify(text2)), text2),
+      ).toBeTruthy();
+      expect(isNodeMetaEqual(text1, text2)).toBeFalsy();
+    });
+
+    it('should compare meta data of two comment nodes', () => {
+      expect(
+        isNodeMetaEqual(comment1, JSON.parse(JSON.stringify(comment1))),
+      ).toBeTruthy();
+      expect(
+        isNodeMetaEqual(JSON.parse(JSON.stringify(comment2)), comment2),
+      ).toBeTruthy();
+      expect(isNodeMetaEqual(comment1, comment2)).toBeFalsy();
+    });
+
+    it('should compare meta data of two HTML elements', () => {
+      expect(
+        isNodeMetaEqual(element1, JSON.parse(JSON.stringify(element1))),
+      ).toBeTruthy();
+      expect(
+        isNodeMetaEqual(JSON.parse(JSON.stringify(element2)), element2),
+      ).toBeTruthy();
+      expect(
+        isNodeMetaEqual(element1, {
+          ...element1,
+          childNodes: [comment2 as serializedNodeWithId],
+        }),
+      ).toBeTruthy();
+      expect(isNodeMetaEqual(element1, element2)).toBeFalsy();
+      expect(isNodeMetaEqual(element1, element3)).toBeFalsy();
+      expect(isNodeMetaEqual(element2, element3)).toBeFalsy();
+    });
+  });
+});