From dd538096ab010af7109220d504d08a7f225f1f8d Mon Sep 17 00:00:00 2001
From: Vladimir Mosyaykin <vladimir.mosyaykin@gmail.com>
Date: Tue, 10 Sep 2024 22:18:17 +0200
Subject: [PATCH] improve defaultValue prop resolution

---
 src/hook/index.test.tsx | 45 ++++++++++++++++++++++++++++++++++++++++-
 src/hook/index.tsx      |  8 ++++++--
 2 files changed, 50 insertions(+), 3 deletions(-)

diff --git a/src/hook/index.test.tsx b/src/hook/index.test.tsx
index 9d4be7a..ecb4aea 100644
--- a/src/hook/index.test.tsx
+++ b/src/hook/index.test.tsx
@@ -13,6 +13,8 @@ import { useFetcher, type Navigation } from "@remix-run/react";
 const submitMock = vi.fn();
 const fetcherSubmitMock = vi.fn();
 
+const useActionDataMock = vi.hoisted(() => vi.fn());
+
 const useNavigationMock = vi.hoisted(() =>
   vi.fn<() => Pick<Navigation, "state" | "formData">>(() => ({
     state: "idle",
@@ -22,7 +24,7 @@ const useNavigationMock = vi.hoisted(() =>
 
 vi.mock("@remix-run/react", () => ({
   useSubmit: () => submitMock,
-  useActionData: () => ({}),
+  useActionData: useActionDataMock,
   useFetcher: () => ({ submit: fetcherSubmitMock, data: {} }),
   useNavigation: useNavigationMock,
 }));
@@ -257,6 +259,47 @@ describe("useRemixForm", () => {
 
     expect(result.current.formState.isSubmitting).toBe(false);
   });
+
+  it("should return defaultValue from the register function", async () => {
+    const { result, rerender } = renderHook(() =>
+      useRemixForm({
+        resolver: () => ({
+          values: { name: "", address: { street: "" } },
+          errors: {},
+        }),
+        defaultValues: {
+          name: "Default name",
+          address: {
+            street: "Default street",
+          },
+        },
+      }),
+    );
+
+    let nameFieldProps = result.current.register("name");
+    let streetFieldProps = result.current.register("address.street");
+
+    expect(nameFieldProps.defaultValue).toBe("Default name");
+    expect(streetFieldProps.defaultValue).toBe("Default street");
+
+    useActionDataMock.mockReturnValue({
+      defaultValues: {
+        name: "Updated name",
+        address: {
+          street: "Updated street",
+        },
+      },
+      errors: { name: "Enter another name" },
+    });
+
+    rerender();
+
+    nameFieldProps = result.current.register("name");
+    streetFieldProps = result.current.register("address.street");
+
+    expect(nameFieldProps.defaultValue).toBe("Updated name");
+    expect(streetFieldProps.defaultValue).toBe("Updated street");
+  });
 });
 
 afterEach(cleanup);
diff --git a/src/hook/index.tsx b/src/hook/index.tsx
index 9f6a65f..14136a3 100644
--- a/src/hook/index.tsx
+++ b/src/hook/index.tsx
@@ -20,6 +20,7 @@ import {
   useFormContext,
   useForm,
   FormProvider,
+  get,
   type DefaultValues,
   type FieldValues,
   type FormState,
@@ -182,10 +183,13 @@ export const useRemixForm = <T extends FieldValues>({
       ) => ({
         ...methods.register(name, options),
         ...(!options?.disableProgressiveEnhancement && {
-          defaultValue: data?.defaultValues?.[name] ?? "",
+          defaultValue:
+            get(data?.defaultValues, name) ??
+            get(methods.formState.defaultValues, name) ??
+            "",
         }),
       }),
-    [methods.register, data?.defaultValues],
+    [methods.register, data?.defaultValues, methods.formState],
   );
 
   const handleSubmit = useMemo(