diff --git a/package.json b/package.json
index 68caff1..87ce35c 100644
--- a/package.json
+++ b/package.json
@@ -24,7 +24,7 @@
     "preview": "vite preview",
     "build-only": "vite build -l error",
     "type-check": "vue-tsc --noEmit",
-    "test:vitest": "vitest",
+    "test": "vitest",
     "postversion": "git push && git push --tags"
   },
   "dependencies": {
diff --git a/src/use/metadata.ts b/src/use/metadata.ts
index ebd4929..1648259 100644
--- a/src/use/metadata.ts
+++ b/src/use/metadata.ts
@@ -251,7 +251,7 @@ export function makeDto(requestDto:string, obj?:any, ctx:{ createResponse?:() =>
     return new dtoCtor(obj)
 }
 
-/** Convert Request DTO values to supported HTML Input values */
+/** Mutates Request DTO values to supported HTML Input values */
 export function toFormValues(dto:any, metaType?:MetadataType|null) {
     if (!dto) return {}
     Object.keys(dto).forEach((key:string) => {
@@ -259,7 +259,7 @@ export function toFormValues(dto:any, metaType?:MetadataType|null) {
         if (typeof value == 'string') {
             if (value.startsWith('/Date'))
                 dto[key] = dateInputFormat(toDate(value))
-        } else if (typeof value == 'object') {
+        } else if (value != null && typeof value == 'object') {
             // shallow clone
             if (Array.isArray(value)) {
                 dto[key] = Array.from(value)
diff --git a/tests/unit/Metadata.spec.ts b/tests/unit/Metadata.spec.ts
new file mode 100644
index 0000000..00375ce
--- /dev/null
+++ b/tests/unit/Metadata.spec.ts
@@ -0,0 +1,15 @@
+import { createApp,h } from 'vue'
+import { test, expect} from 'vitest'
+import { useMetadata } from '../../src/index'
+
+test('toFormValues', () => {
+    const { toFormValues } = useMetadata()
+    const a = { a: "foo", b: 1, c:null }
+    const b = toFormValues(a)
+
+    // toFormValues mutates and returns original argument
+    expect(a === b).true
+    expect(a.a).eq('foo')
+    expect(a.b).eq(1)
+    expect(a.c).eq(null)
+})