From 7e8652e92fbe36e24091387a4d89bf01b9ab01e2 Mon Sep 17 00:00:00 2001
From: kuanghuangshuo <kuanghuangshuo.12@bytedance.com>
Date: Thu, 13 Aug 2026 12:30:37 +0000
Subject: [PATCH] fix(*): type serverValidate decoded values

---
 .changeset/quiet-lamps-warn.md                |  6 ++++++
 .../src/createServerValidate.ts               |  9 ++++-----
 .../tests/createServerValidate.test-d.ts      | 19 +++++++++++++++++++
 .../src/createServerValidate.ts               |  9 ++++-----
 .../tests/createServerValidate.test-d.ts      | 19 +++++++++++++++++++
 5 files changed, 52 insertions(+), 10 deletions(-)
 create mode 100644 .changeset/quiet-lamps-warn.md
 create mode 100644 packages/react-form-nextjs/tests/createServerValidate.test-d.ts
 create mode 100644 packages/react-form-remix/tests/createServerValidate.test-d.ts

diff --git a/.changeset/quiet-lamps-warn.md b/.changeset/quiet-lamps-warn.md
new file mode 100644
index 0000000000..9cd41c0f91
--- /dev/null
+++ b/.changeset/quiet-lamps-warn.md
@@ -0,0 +1,6 @@
+---
+'@tanstack/react-form-nextjs': patch
+'@tanstack/react-form-remix': patch
+---
+
+Fix `createServerValidate` return types to reflect decoded `FormData` values instead of inferred form values.
diff --git a/packages/react-form-nextjs/src/createServerValidate.ts b/packages/react-form-nextjs/src/createServerValidate.ts
index b936f1e8e6..1c1a5631d0 100644
--- a/packages/react-form-nextjs/src/createServerValidate.ts
+++ b/packages/react-form-nextjs/src/createServerValidate.ts
@@ -99,12 +99,11 @@ export const createServerValidate =
       })
     }
 
-    const values = (info
-      ? decode(formData, info)
-      : decode(formData)) as never as TFormData
+    const values = info ? decode(formData, info) : decode(formData)
+    const validationValues = values as never as TFormData
 
     const onServerError = (await runValidator({
-      value: values,
+      value: validationValues,
       validationSource: 'form',
     })) as UnwrapFormAsyncValidateOrFn<TOnServer> | undefined
 
@@ -120,7 +119,7 @@ export const createServerValidate =
       errorMap: {
         onServer: onServerError,
       },
-      values,
+      values: validationValues,
       errors: onServerErrorVal ? [onServerErrorVal] : [],
     }
 
diff --git a/packages/react-form-nextjs/tests/createServerValidate.test-d.ts b/packages/react-form-nextjs/tests/createServerValidate.test-d.ts
new file mode 100644
index 0000000000..14ff7fd857
--- /dev/null
+++ b/packages/react-form-nextjs/tests/createServerValidate.test-d.ts
@@ -0,0 +1,19 @@
+import { expectTypeOf, it } from 'vitest'
+import { createServerValidate, formOptions } from '../src'
+
+it('types serverValidate return values as decoded form data', () => {
+  const serverValidate = createServerValidate({
+    ...formOptions({
+      defaultValues: {
+        firstName: '',
+        age: 0,
+      },
+    }),
+    onServerValidate: async () => undefined,
+  })
+
+  type ServerValidateResult = Awaited<ReturnType<typeof serverValidate>>
+
+  expectTypeOf<ServerValidateResult>().toEqualTypeOf<Record<string, unknown>>()
+  expectTypeOf<ServerValidateResult['age']>().toEqualTypeOf<unknown>()
+})
diff --git a/packages/react-form-remix/src/createServerValidate.ts b/packages/react-form-remix/src/createServerValidate.ts
index b936f1e8e6..1c1a5631d0 100644
--- a/packages/react-form-remix/src/createServerValidate.ts
+++ b/packages/react-form-remix/src/createServerValidate.ts
@@ -99,12 +99,11 @@ export const createServerValidate =
       })
     }
 
-    const values = (info
-      ? decode(formData, info)
-      : decode(formData)) as never as TFormData
+    const values = info ? decode(formData, info) : decode(formData)
+    const validationValues = values as never as TFormData
 
     const onServerError = (await runValidator({
-      value: values,
+      value: validationValues,
       validationSource: 'form',
     })) as UnwrapFormAsyncValidateOrFn<TOnServer> | undefined
 
@@ -120,7 +119,7 @@ export const createServerValidate =
       errorMap: {
         onServer: onServerError,
       },
-      values,
+      values: validationValues,
       errors: onServerErrorVal ? [onServerErrorVal] : [],
     }
 
diff --git a/packages/react-form-remix/tests/createServerValidate.test-d.ts b/packages/react-form-remix/tests/createServerValidate.test-d.ts
new file mode 100644
index 0000000000..14ff7fd857
--- /dev/null
+++ b/packages/react-form-remix/tests/createServerValidate.test-d.ts
@@ -0,0 +1,19 @@
+import { expectTypeOf, it } from 'vitest'
+import { createServerValidate, formOptions } from '../src'
+
+it('types serverValidate return values as decoded form data', () => {
+  const serverValidate = createServerValidate({
+    ...formOptions({
+      defaultValues: {
+        firstName: '',
+        age: 0,
+      },
+    }),
+    onServerValidate: async () => undefined,
+  })
+
+  type ServerValidateResult = Awaited<ReturnType<typeof serverValidate>>
+
+  expectTypeOf<ServerValidateResult>().toEqualTypeOf<Record<string, unknown>>()
+  expectTypeOf<ServerValidateResult['age']>().toEqualTypeOf<unknown>()
+})