MERN Pagination & Sorting - sorting

Question

hopefully, you guys will be able to help me out please.
I can't get the pagination to work properly. It always counts the total documents and ignores the filter data. For example, there are 24 total documents, but when filters by a particular item it returns one, but still returns the total amount of pages (which is 3 as I have pageSize set to 9).
Please find my code below:
router.get('/', async (req, res) => {
try {
const pageSize = 9;
const page = Number(req.query.page) || 1;
let query;
const queryObject = { ...req.query };
const excludeFields = ['page', 'sort', 'limit', 'fields'];
excludeFields.forEach((el) => delete queryObject[el]);
let queryString = JSON.stringify(queryObject);
queryString = queryString.replace(
/\b(gte|gt|lte|lt)\b/g,
(match) => `$${match}`
);
query = Vehicle.find(JSON.parse(queryString));
if (req.query.sort) {
const sortBy = req.query.sort.split(',').join(' ');
query = query.sort(sortBy);
} else {
query = query.sort('-createdAt');
}
const count = await Vehicle.countDocuments();
const vehicles = await Vehicle.find(JSON.parse(queryString))
.limit(pageSize)
.skip(pageSize * (page - 1));
if (!vehicles) {
return res.status(200).json({ success: true, data: [] });
}
res
.status(200)
.json({ vehicles, page, totalPages: Math.ceil(count / pageSize) });
} catch (error) {
console.error(error.message);
res.status(500).send('Server Error');
}
});
How would you go about adding functioning sorting into this also please, for some reason sorting doesn't work at all for me?
Thanks very much, G.

Answer 1

To get the count to include the filtered data you need to add the query parameter in the countDocuments:
const count = await Vehicle.countDocuments(JSON.parse(queryString));
To add sorting functionality you can append .sort() onto the end of you find query:
const vehicles = await Vehicle.find(JSON.parse(queryString))
.limit(pageSize)
.skip(pageSize * (page - 1))
.sort(<your sort query>)
https://www.mongodb.com/community/forums/t/sorting-with-mongoose-and-mongodb/122573