HI I have to add pagination in NodeJS and MongoDB I have done this code

router.get("/PO_pagination", verify, async (req, res) => {
  console.log("req.query", req.query)
  try {
    let { page, size } = req.query
    if (!page) {
      page = 1
    }
    if (!size) {
      size = 10
    }
    const limit = parseInt(size)
    const skip = (page - 1) * size

    const po = await PurchaseOrders.find().limit(limit).skip(skip)
    return res.send({
      page: page,
      size: size,
      data: po
    })
  } catch (error) {
    console.log("error", error)
    return res.status(400).json({ error: error })
  }
})

I am getting data according to req.query but I also want to return the total number of pages on the basis of limit and skip getting from the query like if I said page=1&limit=200 so it arrange a total number of pages according to query params. Also, I want to add the next and prev in res. Like how many pages are next and how many pages are in prev.

CodePudding user response：

You can use countDocuments() to get total number of documents, and then you can calculate your requested data.

router.get("/PO_pagination", verify, async (req, res) => {
  console.log("req.query", req.query)
  try {
    let { page, size } = req.query
    if (!page) page = 1;
    if (!size) size = 10;
    const limit = parseInt(size)
    const skip = (page - 1) * size

    const po = await PurchaseOrders.find().limit(limit).skip(skip);
    const total_documents = await PurchaseOrders.countDocuments();
    
    const previous_pages = page - 1;
    const next_pages = Math.ceil((total_documents-skip)/size);
  
    return res.send({
      page: page,
      size: size,
      data: po,
      previous: previous_pages,
      next: next_pages 
    })
  } catch (error) {
    console.log("error", error)
    return res.status(400).json({ error: error })
  }
})