diff --git a/index.js b/index.js
index e425a8a..4dc4755 100644
--- a/index.js
+++ b/index.js
@@ -2,8 +2,8 @@ const sortby = (properties) => (a, b) => {
   // if items is {prop1:value1, prop2:value2}
   // then sort(['prop1', 'desc', 'prop2'])
   // will sort by prop1 desc and prop2
-  for (var i = 0; i < properties.length; i++) {
-    var property = properties[i]
+  for (let i = 0; i < properties.length; i++) {
+    const property = properties[i]
 
     let order = -1
     if (i + 1 < properties.length && properties[i + 1] === 'desc') {