diff --git a/src/Extendable.ts b/src/Extendable.ts
index 2ebfa98..7d150f8 100644
--- a/src/Extendable.ts
+++ b/src/Extendable.ts
@@ -1,5 +1,8 @@
 import {Type} from "./Utils";
 
+/**
+ * TODO: add has() method
+ */
 export default interface Extendable<ComponentClass> {
     as<C extends ComponentClass>(type: Type<C>): C;