diff --git a/src/store.js b/src/store.js
index 7f479a29d..db8d1cb8b 100644
--- a/src/store.js
+++ b/src/store.js
@@ -29,7 +29,7 @@ export class Store {
       state = {}
     } = options
     if (typeof state === 'function') {
-      state = state()
+      state = state() || {}
     }
 
     // store internal state