我真的不知道为什么，但是当我试图获取数据并将其放入我的响应主体时，它说未定义（在控制台中）。几乎有两个相同的组件。一个使用POST方法并返回一个填充的主体，另一个使用DELETE方法并返回一个未定义的主体。我正在使用Prisma模式。
这是一个POST，它工作并返回API的主体

export default function Product({
  id_product,
  name,
  link_image,
  price,
}: ProductProps) {
  const [test, testing] = useState(false);
  const { push: relocate } = useRouter();

  const onAddToCart = async () => {

    let response = await fetch("/api/addToCart", {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify({
        id_product: id_product,
      }),
    });

    if (response.ok) {
      toast.success(`${name} was added to the cart`);
    } else {
      toast.error(`${name} is already in your cart`);
    }
  };

这是该函数的API的开始，const { id_product } = req.body工作。

async function handlePost(req: NextApiRequest, res: NextApiResponse) {
    const session = await getServerSession(req, res, authOptions);
    const client = connexion()
    const { id_product } = req.body;
 
    const user = await client.user.findFirst({
        where: { email: session?.user?.email || undefined}
    })

    let cart = await client.cart.findFirst({
        where: {id_user: user?.id_user}
    })

这就是我遇到的麻烦，组件基本上是相同的，除了方法：

type ProductProps = products;

export default function ProductItem({
  id_product,
  description,
  publication_date,
  author,
  name,
  link_image,
  price,
}: ProductProps) {
  const onDeleteFromCart = async () => {
    let data = {
      id_product: id_product
    }
    let response = await fetch("/api/deleteFromCart", {
      method: "DELETE",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify(data),
    });
    if (response.ok) {
        toast.success(`${name} was succesfully removed from your cart`)
    }
    else {
        toast.error(`Error`);
      }
  };

这是，const {id_product} = req的API，body未定义

async function handleDelete(req: NextApiRequest, res: NextApiResponse) {
    const session = await getServerSession(req, res, authOptions);
    const client = connexion()
    const  { id_product } = req.body
console.log(id_product)
    const user = await client.user.findFirst({
        where: { email: session?.user?.email || undefined}
    });
 
    let cart = await client.cart.findFirst({
        where: {id_user: user?.id_user}
    });
    let cart_item = await client.cart_item.findFirst({
        where: {
            id_cart: cart?.id,
            id_product: id_product
        }
    })

我已经试着解决这个问题几个小时了，但我一点进展都没有。