返回最近一次 `POST` 导航表单提交中的 `action` 数据，如果没有提交，则返回 `undefined`。
import { Form, useActionData } from "react-router";
export async function action({ request }) {
const body = await request.formData();
const name = body.get("visitorsName");
return { message: `Hello, ${name}` };
}
export default function Invoices() {
const data = useActionData();
return (
<Form method="post">
<input type="text" name="visitorsName" />
{data ? data.message : "Waiting..."}
</Form>
);
}
function useActionData<T = any>(): SerializeFrom<T> | undefined