How to use getKey?

[nehiro]

Hi, I don't know how to use limit and pageIndex. Now fetcer fetches the data for all the books.
Could you please tell me how to fix it?

const limit = 5;

  const getKey = (pageIndex: number, previousPageData: any) => {
    if (previousPageData && !previousPageData.length) return null;
    return `http://localhost:3000/api/books?page=${
      pageIndex + 1
    }&limit=${limit}`;
  };

  const { data, size, setSize } = useSWRInfinite(
    getKey,
    (url) =>
      fetch(url, {
        method: 'GET',
      }).then((r) => r.json()),
    {
      initialSize: 1,
    }
  );

/api/books

const handler = async (req: NextApiRequest, res: NextApiResponse<Response>) => {
  console.log(req.query, 'req.query');
  try {
    switch (req.method) {
      case 'GET':
        return res.status(200).json(db);
    }
    return res.status(200).send('OK');
  } catch (error) {
    console.log(error);
    return res.status(500).send('Internal Server Error');
  }
};

[nehiro]

Resolved. I did not know how to use slice().

if (page > 1) {
  const result = data.slice(limit * page - limit, limit * page);
  return res.status(200).json(result);
} else {
  const result = data.slice(0, limit);
  return res.status(200).json(result);
}