From 91bdd6e2c852071efe3cd01f2f23d6162e5861ed Mon Sep 17 00:00:00 2001
From: Eoghan Murray <eoghan@getthere.ie>
Date: Wed, 1 Apr 2026 12:00:00 +0800
Subject: [PATCH] No neg lookbehind (#1493)

* Older versions of Safari 16 don't support lookbehind assertions - https://caniuse.com/js-regexp-lookbehind

* Refactor to show the similarity between these two regexes

* Apply formatting changes

* Create no-neg-lookbehind.md

---------

Co-authored-by: eoghanmurray <eoghanmurray@users.noreply.github.com>
---
 .changeset/no-neg-lookbehind.md     |  6 ++++++
 .changeset/silent-plants-perform.md |  2 +-
 packages/rrweb-snapshot/src/css.ts  | 18 ++++++++++++++----
 3 files changed, 21 insertions(+), 5 deletions(-)
 create mode 100644 .changeset/no-neg-lookbehind.md

diff --git a/.changeset/no-neg-lookbehind.md b/.changeset/no-neg-lookbehind.md
new file mode 100644
index 00000000..f152328e
--- /dev/null
+++ b/.changeset/no-neg-lookbehind.md
@@ -0,0 +1,6 @@
+---
+"rrweb-snapshot": patch
+"rrweb": patch
+---
+
+Replay: Replace negative lookbehind in regexes from css parser as it causes issues with Safari 16
diff --git a/.changeset/silent-plants-perform.md b/.changeset/silent-plants-perform.md
index b87aaa90..1b234ec2 100644
--- a/.changeset/silent-plants-perform.md
+++ b/.changeset/silent-plants-perform.md
@@ -1,5 +1,5 @@
 ---
-'rrweb': patch
+"rrweb": patch
 ---
 
 Return early for child same origin frames
diff --git a/packages/rrweb-snapshot/src/css.ts b/packages/rrweb-snapshot/src/css.ts
index 220e1a1f..7aeb0d8a 100644
--- a/packages/rrweb-snapshot/src/css.ts
+++ b/packages/rrweb-snapshot/src/css.ts
@@ -424,6 +424,17 @@ export function parse(css: string, options: ParserOptions = {}): Stylesheet {
    * Parse selector.
    */
 
+  // originally from https://github.com/NxtChg/pieces/blob/3eb39c8287a97632e9347a24f333d52d916bc816/js/css_parser/css_parse.js#L46C1-L47C1
+  const selectorMatcher = new RegExp(
+    '^((' +
+      [
+        /[^\\]"(?:\\"|[^"])*"/.source, // consume any quoted parts (checking that the double quote isn't itself escaped)
+        /[^\\]'(?:\\'|[^'])*'/.source, // same but for single quotes
+        '[^{]',
+      ].join('|') +
+      ')+)',
+  );
+
   function selector() {
     whitespace();
     while (css[0] == '}') {
@@ -432,8 +443,7 @@ export function parse(css: string, options: ParserOptions = {}): Stylesheet {
       whitespace();
     }
 
-    // Use match logic from https://github.com/NxtChg/pieces/blob/3eb39c8287a97632e9347a24f333d52d916bc816/js/css_parser/css_parse.js#L46C1-L47C1
-    const m = match(/^(((?<!\\)"(?:\\"|[^"])*"|(?<!\\)'(?:\\'|[^'])*'|[^{])+)/);
+    const m = match(selectorMatcher);
     if (!m) {
       return;
     }
@@ -869,8 +879,8 @@ export function parse(css: string, options: ParserOptions = {}): Stylesheet {
         name +
         '\\s*((?:' +
         [
-          '(?<!\\\\)"(?:\\\\"|[^"])*"',
-          "(?<!\\\\)'(?:\\\\'|[^'])*'",
+          /[^\\]"(?:\\"|[^"])*"/.source, // consume any quoted parts (checking that the double quote isn't itself escaped)
+          /[^\\]'(?:\\'|[^'])*'/.source, // same but for single quotes
           '[^;]',
         ].join('|') +
         ')+);',