docs: tips for form reset with default value from loader (#666)

docs/integration/remix.md

@@ -83,3 +83,28 @@ export default function Login() {
   );
 }
 ```
+
+## Tips
+
+### The default value might be out of sync if you reset the form from the action
+
+If the default value of the form comes from the loader and you are trying to reset the form on the action, there is a chance you will see the form reset to the previous default value. This is Conform will reset the form the moment actionData is updated while Remix is still revalidating the loader data. To fix this, you can wait for the state to be `idle` (e.g. `navigation.state` or `fetcher.state`) before passing the `lastResult` to Conform like this:
+
+```tsx
+export default function Example() {
+  const { defaultValue } = useLoaderData<typeof loader>();
+  const lastResult = useActionData<typeof action>();
+  const navigation = useNavigation();
+  const [form, fields] = useForm({
+    // If the default value comes from loader
+    defaultValue,
+
+    // Sync the result of last submission only when the state is idle
+    lastResult: navigation.state === 'idle' ? lastResult : null,
+
+    // ...
+  });
+
+  // ...
+}
+```