diff --git a/lib/parent-dummy-chains.js b/lib/parent-dummy-chains.js
index 59e95ab4..8103ab3f 100644
--- a/lib/parent-dummy-chains.js
+++ b/lib/parent-dummy-chains.js
@@ -1,17 +1,17 @@
 module.exports = parentDummyChains;
 
 function parentDummyChains(g) {
-  var postorderNums = postorder(g);
+  let postorderNums = postorder(g);
 
   g.graph().dummyChains.forEach(v => {
-    var node = g.node(v);
-    var edgeObj = node.edgeObj;
-    var pathData = findPath(g, postorderNums, edgeObj.v, edgeObj.w);
-    var path = pathData.path;
-    var lca = pathData.lca;
-    var pathIdx = 0;
-    var pathV = path[pathIdx];
-    var ascending = true;
+    let node = g.node(v);
+    let edgeObj = node.edgeObj;
+    let pathData = findPath(g, postorderNums, edgeObj.v, edgeObj.w);
+    let path = pathData.path;
+    let lca = pathData.lca;
+    let pathIdx = 0;
+    let pathV = path[pathIdx];
+    let ascending = true;
 
     while (v !== edgeObj.w) {
       node = g.node(v);