From ec8473b5e4a8a5f0f2b516317eeb3271d06ac1a6 Mon Sep 17 00:00:00 2001
From: Yanzhen Yu <yanzhen@smartx.com>
Date: Wed, 1 Apr 2026 12:00:00 +0800
Subject: [PATCH] ignore prefetch and preload script links

related to:
1. https://github.com/rrweb-io/rrweb/issues/52
2. https://github.com/rrweb-io/rrweb/issues/297
3. https://github.com/rrweb-io/rrweb/issues/597
---
 src/rebuild.ts                         | 23 +++++++++++++++++++----
 src/snapshot.ts                        | 13 ++++++++++---
 test/__snapshots__/integration.ts.snap | 11 +++++++++++
 test/html/preload.html                 | 11 +++++++++++
 4 files changed, 51 insertions(+), 7 deletions(-)
 create mode 100644 test/html/preload.html

diff --git a/src/rebuild.ts b/src/rebuild.ts
index c9322536..a0778a0c 100644
--- a/src/rebuild.ts
+++ b/src/rebuild.ts
@@ -58,8 +58,8 @@ function getTagName(n: elementNode): string {
 }
 
 // based on https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#escaping
-function escapeRegExp(string: string) {
-  return string.replace(/[.*+?^${}()|[\]\\]/g, '\\$&'); // $& means the whole matched string
+function escapeRegExp(str: string) {
+  return str.replace(/[.*+?^${}()|[\]\\]/g, '\\$&'); // $& means the whole matched string
 }
 
 const HOVER_SELECTOR = /([^\\]):hover/;
@@ -84,7 +84,9 @@ export function addHoverClass(cssText: string): string {
     }
   });
 
-  if (selectors.length === 0) return cssText;
+  if (selectors.length === 0) {
+    return cssText;
+  }
 
   const selectorMatcher = new RegExp(
     selectors
@@ -170,12 +172,25 @@ function buildNode(
             } else if (
               tagName === 'meta' &&
               n.attributes['http-equiv'] === 'Content-Security-Policy' &&
-              name == 'content'
+              name === 'content'
             ) {
               // If CSP contains style-src and inline-style is disabled, there will be an error "Refused to apply inline style because it violates the following Content Security Policy directive: style-src '*'".
               // And the function insertStyleRules in rrweb replayer will throw an error "Uncaught TypeError: Cannot read property 'insertRule' of null".
               node.setAttribute('csp-content', value);
               continue;
+            } else if (
+              tagName === 'link' &&
+              n.attributes.rel === 'preload' &&
+              n.attributes.as === 'script'
+            ) {
+              // ignore
+            } else if (
+              tagName === 'link' &&
+              n.attributes.rel === 'prefetch' &&
+              typeof n.attributes.href === 'string' &&
+              n.attributes.href.endsWith('.js')
+            ) {
+              // ignore
             } else {
               node.setAttribute(name, value);
             }
diff --git a/src/snapshot.ts b/src/snapshot.ts
index f412cbfd..49c2e13c 100644
--- a/src/snapshot.ts
+++ b/src/snapshot.ts
@@ -369,8 +369,8 @@ function serializeNode(
   } = options;
   // Only record root id when document object is not the base document
   let rootId: number | undefined;
-  if ((doc as unknown as INode).__sn) {
-    const docId = (doc as unknown as INode).__sn.id;
+  if (((doc as unknown) as INode).__sn) {
+    const docId = ((doc as unknown) as INode).__sn.id;
     rootId = docId === 1 ? undefined : docId;
   }
   switch (n.nodeType) {
@@ -568,10 +568,17 @@ function slimDOMExcluded(
   } else if (sn.type === NodeType.Element) {
     if (
       slimDOMOptions.script &&
+      // script tag
       (sn.tagName === 'script' ||
+        // preload link
         (sn.tagName === 'link' &&
           sn.attributes.rel === 'preload' &&
-          sn.attributes.as === 'script'))
+          sn.attributes.as === 'script') ||
+        // prefetch link
+        (sn.tagName === 'link' &&
+          sn.attributes.rel === 'prefetch' &&
+          typeof sn.attributes.href === 'string' &&
+          sn.attributes.href.endsWith('.js')))
     ) {
       return true;
     } else if (
diff --git a/test/__snapshots__/integration.ts.snap b/test/__snapshots__/integration.ts.snap
index cd30b31c..e087f79b 100644
--- a/test/__snapshots__/integration.ts.snap
+++ b/test/__snapshots__/integration.ts.snap
@@ -226,6 +226,17 @@ exports[`[html file]: picture.html 1`] = `
   </body></html>"
 `;
 
+exports[`[html file]: preload.html 1`] = `
+"<!DOCTYPE html><html xmlns=\\"http://www.w3.org/1999/xhtml\\" lang=\\"en\\"><head>
+    <meta charset=\\"UTF-8\\" />
+    <meta name=\\"viewport\\" content=\\"width=device-width, initial-scale=1.0\\" />
+    <title>Document</title>
+    <link />
+    <link />
+  </head>
+  <body></body></html>"
+`;
+
 exports[`[html file]: shadow-dom.html 1`] = `
 "<!DOCTYPE html><html xmlns=\\"http://www.w3.org/1999/xhtml\\" lang=\\"en\\"><head>
     <meta charset=\\"UTF-8\\" />
diff --git a/test/html/preload.html b/test/html/preload.html
new file mode 100644
index 00000000..32e84a26
--- /dev/null
+++ b/test/html/preload.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+    <title>Document</title>
+    <link rel="preload" href="https://example/path/to/preload.js" as="script" />
+    <link rel="prefetch" href="https://example/path/to/prefetch.js" />
+  </head>
+  <body></body>
+</html>