diff --git a/lib/request.js b/lib/request.js
index 7c27901..48c7b6a 100644
--- a/lib/request.js
+++ b/lib/request.js
@@ -259,8 +259,8 @@ module.exports = {
    */
 
   get idempotent() {
-    var idempotents = ['GET','HEAD','PUT','DELETE','OPTIONS','TRACE'];
-    return idempotents.indexOf(this.method) !== -1;
+    var methods = ['GET', 'HEAD', 'PUT', 'DELETE', 'OPTIONS', 'TRACE'];
+    return ~methods.indexOf(this.method);
   },
 
   /**