diff --git a/src/transformState.js b/src/transformState.js
index 3f96c4f4..05009e86 100644
--- a/src/transformState.js
+++ b/src/transformState.js
@@ -25,6 +25,9 @@ function transformState(state, actions) {
         }
 
         break;
+
+      default:
+        throw new Error();
     }
   };
 }