diff --git a/packages/rrweb/src/record/mutation.ts b/packages/rrweb/src/record/mutation.ts
index 02a8867a64..a798441969 100644
--- a/packages/rrweb/src/record/mutation.ts
+++ b/packages/rrweb/src/record/mutation.ts
@@ -739,7 +739,7 @@ export default class MutationBuffer {
   /**
    * Make sure you check if `n`'s parent is blocked before calling this function
    * */
-  private genAdds(n: Node, target?: Node) {
+  private genAdds = (n: Node, target?: Node) => {
     // this node was already recorded in other buffer, ignore it
     if (this.processedNodeManager.inOtherBuffer(n, this)) return;
 
@@ -774,7 +774,7 @@ export default class MutationBuffer {
         });
       }
     }
-  }
+  };
 }
 
 /**