Merge branch 'master' into fix/140-update-handle-change-type

Author: larrybotha

.lintstagedrc.js

@@ -1,3 +1,3 @@
 module.exports = {
-  '*!(.eslintrc).{svelte,js,ts}': ['eslint', 'prettier --write'],
+  '*.{svelte,js}': ['eslint', 'prettier --write'],
 };

lib/index.d.ts

@@ -97,4 +97,6 @@ declare class ErrorMessage extends SvelteComponentTyped<
   {default: any}
 > {}
 
-export {createForm, Form, Field, Select, ErrorMessage, Textarea};
+declare const key: {};
+
+export {createForm, key, Form, Field, Select, ErrorMessage, Textarea};

lib/util.js

@@ -84,7 +84,7 @@ function assignDeep(object, value) {
   const copy = {};
   for (const key in object) {
     copy[key] =
-      typeof object[key] === 'object' ? assignDeep(object[key], value) : value;
+      typeof object[key] === 'object' && !isNullish(object[key]) ? assignDeep(object[key], value) : value;
   }
   return copy;
 }