diff --git a/sort/quick-sort.mjs b/sort/quick-sort.mjs
index c0b5dd4..f644e04 100644
--- a/sort/quick-sort.mjs
+++ b/sort/quick-sort.mjs
@@ -160,7 +160,7 @@ export function quickSort4(arr) {
       stack.push(pivot - 1);
       stack.push(l);
     }
-    if (right > pivot + 1) {
+    if (r > pivot + 1) {
       stack.push(r);
       stack.push(pivot + 1);
     }