diff --git a/src/edgesum.js b/src/edgesum.js
index 675c269..723b10d 100644
--- a/src/edgesum.js
+++ b/src/edgesum.js
@@ -6,14 +6,11 @@ export function edgesum(graph, order) {
 
   const inv = inverse_permutation(order);
   const links = graph.links();
-  let i;
-  let e;
-  let d;
   let sum = 0;
 
-  for (i = 0; i < links.length; i++) {
-    e = links[i];
-    d = Math.abs(inv[e.source.index] - inv[e.target.index]);
+  for (let i = 0; i < links.length; i++) {
+    const e = links[i];
+    const d = Math.abs(inv[e.source.index] - inv[e.target.index]);
     sum += d;
   }
   return sum;