diff --git a/src/core/ReactEmptyComponent.js b/src/core/ReactEmptyComponent.js
index 98de938b098e..8c8b2cc37427 100644
--- a/src/core/ReactEmptyComponent.js
+++ b/src/core/ReactEmptyComponent.js
@@ -59,7 +59,7 @@ function deregisterNullComponentID(id) {
  * @return {boolean} True if the component is rendered to null.
  */
 function isNullComponentID(id) {
-  return nullComponentIdsRegistry[id];
+  return !!nullComponentIdsRegistry[id];
 }
 
 var ReactEmptyComponent = {