diff --git a/lib/utils/objects.js b/lib/utils/objects.js
index dc453fe..f0ba6cb 100644
--- a/lib/utils/objects.js
+++ b/lib/utils/objects.js
@@ -45,7 +45,7 @@ Objects.prototype.pick = function (category, last) {
 }
 
 Objects.prototype.pop = function (objectName) {
-  var self = this
+  let self = this
   utils.getKeysFromHash(this.container).forEach(function (category) {
     self.container[category].forEach(function (obj) {
       if (obj.name === objectName) {
@@ -56,8 +56,8 @@ Objects.prototype.pop = function (objectName) {
 }
 
 Objects.prototype.contains = function (categoryNames) {
-  var categories = []
-  var self = this
+  let categories = []
+  let self = this
   categoryNames.forEach(function (name) {
     if (self.has(name)) {
       categories.push(name)
@@ -83,13 +83,13 @@ Objects.prototype.has = function (category) {
 }
 
 Objects.prototype.valid = function () {
-  var items = []
-  var self = this
+  let items = []
+  let self = this
   utils.common.getKeysFromHash(self.container).forEach(function (category) {
     self.check(category)
   })
   utils.common.getKeysFromHash(self.container).forEach(function (category) {
-    for (var i = 0; i < self.container[category].length; i++) {
+    for (let i = 0; i < self.container[category].length; i++) {
       items.push(self.container[category][i].name)
     }
   })
@@ -97,7 +97,7 @@ Objects.prototype.valid = function () {
 }
 
 Objects.prototype.check = function (category) {
-  var self = this
+  let self = this
   self.container[category].forEach(function (object) {
     try {
       let x = /* frame.contentWindow. */ eval(object.name) // eslint-disable-line no-eval