use WeakMap for faster attributeCursor lookup

pendo-io · Nov 3, 2023 · fed3647 · fed3647
1 parent 8444cb2
commit fed3647
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Showing 2 changed files with 9 additions and 3 deletions.
diff --git a/.changeset/moody-dots-refuse.md 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
@@ -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