diff --git a/lib/types/json.js b/lib/types/json.js
index bc2de83..901b16c 100644
--- a/lib/types/json.js
+++ b/lib/types/json.js
@@ -241,7 +241,5 @@ function normalizeJsonSyntaxError (error, obj) {
  */
 
 function typeChecker (type) {
-  return function checkType (req) {
-    return Boolean(typeis(req, type))
-  }
+  return (req) => Boolean(typeis(req, type))
 }