How to Implement Pagination in Node.js: Simple Guide

To implement pagination in Node.js, use query parameters like page and limit to control which data slice to fetch. Calculate the skip value as (page - 1) * limit and use it with your database query to return only the needed records.

Syntax

Pagination in Node.js typically uses two query parameters: page (current page number) and limit (items per page). You calculate skip to tell the database how many items to skip before starting to return results.

• page: Which page of results to show (starts at 1).
• limit: How many items to show per page.
• skip: Number of items to skip, calculated as (page - 1) * limit.

javascript

const page = parseInt(req.query.page) || 1;
const limit = parseInt(req.query.limit) || 10;
const skip = (page - 1) * limit;

// Example with MongoDB
const results = await collection.find().skip(skip).limit(limit).toArray();

Example

This example shows a simple Express.js route that returns paginated user data from a MongoDB collection. It reads page and limit from the query string, calculates skip, and fetches only the requested slice of users.

javascript

import express from 'express';
import { MongoClient } from 'mongodb';

const app = express();
const client = new MongoClient('mongodb://localhost:27017');

async function main() {
  await client.connect();
  const db = client.db('testdb');
  const users = db.collection('users');

  app.get('/users', async (req, res) => {
    const page = parseInt(req.query.page) || 1;
    const limit = parseInt(req.query.limit) || 5;
    const skip = (page - 1) * limit;

    const results = await users.find().skip(skip).limit(limit).toArray();
    res.json({ page, limit, results });
  });

  app.listen(3000, () => console.log('Server running on http://localhost:3000'));
}

main().catch(console.error);

Output

{"page":1,"limit":5,"results":[{"_id":"...","name":"User1"},{"_id":"...","name":"User2"},{"_id":"...","name":"User3"},{"_id":"...","name":"User4"},{"_id":"...","name":"User5"}]}

Common Pitfalls

Common mistakes when implementing pagination include:

• Not validating page and limit values, which can cause errors or performance issues.
• Using skip with very large offsets, which can slow down database queries.
• Not returning total count or next page info, making it hard for clients to know when to stop.

Always sanitize inputs and consider adding total count for better UX.

javascript

/* Wrong: No validation, can cause negative skip */
const page = parseInt(req.query.page);
const limit = parseInt(req.query.limit);
const skip = (page - 1) * limit; // if page=0, skip=-limit (bad)

/* Right: Validate and set defaults */
const pageSafe = Math.max(parseInt(req.query.page) || 1, 1);
const limitSafe = Math.min(Math.max(parseInt(req.query.limit) || 10, 1), 100); // max 100
const skipSafe = (pageSafe - 1) * limitSafe;

Quick Reference

Summary tips for pagination in Node.js:

• Use page and limit query parameters.
• Calculate skip = (page - 1) * limit for database queries.
• Validate and sanitize inputs to avoid errors.
• Return total count or next page info for better client experience.
• Consider performance impact of large skip values.

Key Takeaways

Use query parameters page and limit to control pagination in Node.js.

Calculate skip as (page - 1) * limit to fetch the correct data slice.

Always validate and sanitize page and limit values to avoid errors.

Return total count or next page info to help clients navigate pages.

Be aware that large skip values can slow down database queries.