Fix bug with components that don't have an initial callback function

Author: sebastienfilion

.gitignore

@@ -13,3 +13,5 @@ journal/
 *.zip
 
 .todo.md
+
+build/

library/component.ts

@@ -660,7 +660,7 @@ export const useCallbacks = <
             configurable: true,
             enumerable: true,
             value(...xs: [string, string, string]) {
-              return maybeCall(() => g.call(this, ...xs))
+              return maybeCall(() => g && g.call(this, ...xs))
                 .then(() =>
                   f(
                     this,