diff --git a/lib/adapters/xhr.js b/lib/adapters/xhr.js
index 4cda89a..bf90efd 100644
--- a/lib/adapters/xhr.js
+++ b/lib/adapters/xhr.js
@@ -169,7 +169,7 @@ module.exports = function xhrAdapter(config) {
       });
     }
 
-    if (requestData === undefined) {
+    if (!requestData) {
       requestData = null;
     }