Prerequisites: Basic knowledge of Nodejs and Mongodb.

What is pagination ?

Ans: Consider that you have around 1 million records that you want to fetch. But fetching 1 million record at once will take alot of time and its not good practice to fetch huge data at once. So, there comes Pagination where users can fetch data in pages. This is achieved by using options skip and limit, giving clients full control of the page(data) they are getting back.

When to use Pagination?

As its statement describes, Pagination should be used:

• When clients should have the control of data they are getting back.
• Improving User Experience(UX) and Better Navigation.
• When fetching huge data.

What are the ways in which you can implement Pagination in NodeJs?

Well, there could be multiple ways, which you could use to implement Pagination in nodejs but in this post i am gonna talk about two main ways in which we can implement Pagination. Those two ways are as follows:

• Offset based pagination (skip and limit)
• Cursor based pagination

In this post I am gonna talk only about Offset Based Pagination. For Cursor based pagination you can check out my this post.

Offset based pagination:

It is one of the most common pagination methods we are using for decades. It simply uses limit and offset in SQL queries to paginate the data from database.

In NOSQL database, it will be limit and skip. Let’s implement it in our application and see the advantages/disadvantages of it. Implementation for offset pagination is straightforward,

  const fetchCompanies = async (req, res) => {
   constlimit=parseInt(req.query.limit);
   constoffset=parseInt(req.query.skip);
   try {

    consttradesCollection=await Trades.find().skip(offset).limit(limit);

    consttradesCollectionCount=await Trades.count();
    consttotalPages=Math.ceil(tradesCollectionCount/limit);
    constcurrentPage=Math.ceil(tradesCollectionCount%offset);

    res.status(200).send({
     data: tradesCollection,
     paging: {
     total: tradesCollectionCount,
     page: currentPage,
     pages: totalPages,
    },
   });

 } catch (e) {
  console.log("Error", e);
  res.status(500).send({
  data: null,
});

const tradesCollection = await Trades.find().skip(offset).limit(limit);

res.status(200).send({
 data: tradesCollection,
 paging: {
  total: tradesCollectionCount,
  page: currentPage,
  pages: totalPages,
 },
});