diff --git a/config/application.rb b/config/application.rb
index 31f975d538b8872f36573d28166077c1379e4ac9..8bbecf3ed0f5287cd2b45e62406b5ea7f27a6526 100644
--- a/config/application.rb
+++ b/config/application.rb
@@ -104,7 +104,6 @@ module Gitlab
     config.assets.precompile << "mailers/*.css"
     config.assets.precompile << "katex.css"
     config.assets.precompile << "katex.js"
-    config.assets.precompile << "peek.js"
     config.assets.precompile << "xterm/xterm.css"
     config.assets.precompile << "peek.css"
     config.assets.precompile << "lib/ace.js"
diff --git a/vendor/assets/javascripts/peek.js b/vendor/assets/javascripts/peek.js
index 427a8a3efadfa22ffbabe3dcc9b3c177e9581db6..f7e77de34ff36138bf2d754b3664c05ab5d68378 100644
--- a/vendor/assets/javascripts/peek.js
+++ b/vendor/assets/javascripts/peek.js
@@ -9,8 +9,8 @@
   updatePerformanceBar = function(results) {
     var key, label, data, table, html, tr, duration_td, sql_td, strong;
 
-    Object.keys(results.data).forEach((key) => {
-      Object.keys(results.data[key]).forEach((label) => {
+    Object.keys(results.data).forEach(function(key) {
+      Object.keys(results.data[key]).forEach(function(label) {
         data = results.data[key][label];
 
         if (label == 'queries') {