From fed3647a1256e9c99f270671b7af3b675ba21671 Mon Sep 17 00:00:00 2001
From: Michael Dellanoce <mdellanoce@pendo.io>
Date: Thu, 26 Oct 2023 13:17:40 -0400
Subject: [PATCH] use WeakMap for faster attributeCursor lookup

---
 .changeset/moody-dots-refuse.md       | 5 +++++
 packages/rrweb/src/record/mutation.ts | 7 ++++---
 2 files changed, 9 insertions(+), 3 deletions(-)
 create mode 100644 .changeset/moody-dots-refuse.md

diff --git a/.changeset/moody-dots-refuse.md b/.changeset/moody-dots-refuse.md
new file mode 100644
index 0000000000..32270da384
--- /dev/null
+++ b/.changeset/moody-dots-refuse.md
@@ -0,0 +1,5 @@
+---
+'rrweb': patch
+---
+
+use WeakMap for faster attributeCursor lookup while processing attribute mutations
diff --git a/packages/rrweb/src/record/mutation.ts b/packages/rrweb/src/record/mutation.ts
index 80943d96ab..440f308696 100644
--- a/packages/rrweb/src/record/mutation.ts
+++ b/packages/rrweb/src/record/mutation.ts
@@ -142,6 +142,7 @@ export default class MutationBuffer {
 
   private texts: textCursor[] = [];
   private attributes: attributeCursor[] = [];
+  private attributeMap = new WeakMap<Node, attributeCursor>();
   private removes: removedNodeMutation[] = [];
   private mapRemoves: Node[] = [];
 
@@ -485,6 +486,7 @@ export default class MutationBuffer {
     // reset
     this.texts = [];
     this.attributes = [];
+    this.attributeMap = new WeakMap<Node, attributeCursor>();
     this.removes = [];
     this.addedSet = new Set<Node>();
     this.movedSet = new Set<Node>();
@@ -554,9 +556,7 @@ export default class MutationBuffer {
           return;
         }
 
-        let item: attributeCursor | undefined = this.attributes.find(
-          (a) => a.node === m.target,
-        );
+        let item = this.attributeMap.get(m.target);
         if (
           target.tagName === 'IFRAME' &&
           attributeName === 'src' &&
@@ -578,6 +578,7 @@ export default class MutationBuffer {
             _unchangedStyles: {},
           };
           this.attributes.push(item);
+          this.attributeMap.set(m.target, item);
         }
 
         // Keep this property on inputs that used to be password inputs