diff --git a/.rubocop.yml b/.rubocop.yml
index aa03067584..f4c0692286 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -365,6 +365,7 @@ Naming/FileName:
     - 'stdlib/opal-parser.rb'
     - 'stdlib/opal-platform.rb'
     - 'stdlib/opal-source-maps.rb'
+    - 'stdlib/opal-replutils.rb'
 
 Naming/ConstantName:
   Exclude:
diff --git a/stdlib/opal-replutils.rb b/stdlib/opal-replutils.rb
index f8b3d63101..fda275ec12 100644
--- a/stdlib/opal-replutils.rb
+++ b/stdlib/opal-replutils.rb
@@ -65,7 +65,7 @@ def eval_and_print(func, mode, colorize)
 
       if (mode == 'silent') return nil;
 
-      if (typeof $_result === 'null') {
+      if ($_result === null) {
         return "=> null";
       }
       else if (typeof $_result === 'undefined') {