如何将分页应用于json-server中的子对象？

{
  "users": [
    {
      "id": 1,
      "name": "John",
      "posts": [
        {
          "id": 1,
          "title": "Post 1"
        },
        {
          "id": 2,
          "title": "Post 2"
        }
      ]
    },
    {
      "id": 2,
      "name": "Jane",
      "posts": [
        {
          "id": 3,
          "title": "Post 3"
        },
        {
          "id": 4,
          "title": "Post 4"
        }
      ]
    }
  ]
}

{
  "/users/:userId/posts": "/users/:userId/posts"
}

module.exports = (req, res, next) => {
  if (req.originalUrl.includes('/users/') && req.originalUrl.includes('/posts')) {
    const userId = req.originalUrl.split('/users/')[1].split('/posts')[0];
    const user = db.get('users').find({ id: parseInt(userId) }).value();
    const posts = user ? user.posts : [];
    
    const page = parseInt(req.query._page) || 1;
    const limit = parseInt(req.query._limit) || 10;
    const startIndex = (page - 1) * limit;
    const endIndex = page * limit;
    const paginatedPosts = posts.slice(startIndex, endIndex);
    
    res.setHeader('X-Total-Count', posts.length);
    res.setHeader('X-Total-Pages', Math.ceil(posts.length / limit));
    res.setHeader('X-Current-Page', page);
    
    res.json(paginatedPosts);
  } else {
    next();
  }
};

json-server --watch db.json --routes routes.json --middlewares middlewares.js