diff --git a/lib/data/list.js b/lib/data/list.js
index b4472103..71a69858 100644
--- a/lib/data/list.js
+++ b/lib/data/list.js
@@ -5,14 +5,14 @@
 
 class List {
   constructor() {
-    var sentinel = {};
+    let sentinel = {};
     sentinel._next = sentinel._prev = sentinel;
     this._sentinel = sentinel;
   }
 
   dequeue() {
-    var sentinel = this._sentinel;
-    var entry = sentinel._prev;
+    let sentinel = this._sentinel;
+    let entry = sentinel._prev;
     if (entry !== sentinel) {
       unlink(entry);
       return entry;
@@ -20,7 +20,7 @@ class List {
   }
 
   enqueue(entry) {
-    var sentinel = this._sentinel;
+    let sentinel = this._sentinel;
     if (entry._prev && entry._next) {
       unlink(entry);
     }
@@ -31,9 +31,9 @@ class List {
   }
 
   toString() {
-    var strs = [];
-    var sentinel = this._sentinel;
-    var curr = sentinel._prev;
+    let strs = [];
+    let sentinel = this._sentinel;
+    let curr = sentinel._prev;
     while (curr !== sentinel) {
       strs.push(JSON.stringify(curr, filterOutLinks));
       curr = curr._prev;