Implementing pagination controller in Node.js | Hindi tutorial on Node.js

To create a pagination controller in Node.js, you will need to use libraries such as Express.js and Mongoose for interacting with MongoDB. Pagination allows you to break down a large set of data into multiple pages, making it easier for users to navigate through the data. In this tutorial, we will be writing a sample pagination controller using Node.js and Express.js.

Step 1: Create a new Node.js project
First, you need to create a new Node.js project by running the following command in your terminal:

mkdir pagination-nodejs
cd pagination-nodejs
npm init -y

Step 2: Install the required dependencies
Next, you need to install the required dependencies, which include Express.js and Mongoose. Run the following command in your terminal:

npm install express mongoose

Step 3: Set up Express.js server
Create a new file called app.js and paste the following code:

const express = require('express');
const app = express();

app.use(express.json());

app.listen(3000, () => {
  console.log(`Server is running on port 3000`);
});

Step 4: Connect to MongoDB
Create a new file called db.js and paste the following code to connect to MongoDB:

const mongoose = require('mongoose');

mongoose.connect('mongodb://localhost:27017/pagination', {
  useNewUrlParser: true,
  useUnifiedTopology: true,
})
.then(() => {
  console.log('Connected to MongoDB');
})
.catch((error) => {
  console.log('Error connecting to MongoDB', error);
});

Step 5: Create a model
Create a new file called model.js and paste the following code to create a sample model:

const mongoose = require('mongoose');

const userSchema = new mongoose.Schema({
  name: String,
  age: Number,
});

const User = mongoose.model('User', userSchema);

module.exports = User;

Step 6: Create a pagination controller
Create a new file called paginationController.js and paste the following code:

const User = require('./model');

const getPaginatedUsers = async (req, res) => {
  const page = parseInt(req.query.page) || 1;
  const limit = parseInt(req.query.limit) || 10;

  const startIndex = (page - 1) * limit;
  const endIndex = page * limit;

  const results = {};

  if (endIndex < await User.countDocuments().exec()) {
    results.next = {
      page: page + 1,
      limit: limit,
    };
  }

  if (startIndex > 0) {
    results.previous = {
      page: page - 1,
      limit: limit,
    };
  }

  results.results = await User.find().limit(limit).skip(startIndex).exec();

  res.json(results);
};

module.exports = { getPaginatedUsers };

Step 7: Update app.js
Update the app.js file to include the pagination controller:

const express = require('express');
const app = express();
const { getPaginatedUsers } = require('./paginationController');
require('./db');

app.use(express.json());

app.get('/users', getPaginatedUsers);

app.listen(3000, () => {
  console.log(`Server is running on port 3000`);
});

Step 8: Run the server
Run the following command in your terminal to start the server:

node app.js

You can now access the pagination API by visiting http://localhost:3000/users?page=1&limit=10. This will return the first page of users with a limit of 10 users per page. You can customize the page and limit parameters to navigate through the data.

This concludes the tutorial on creating a pagination controller in Node.js using Express.js and Mongoose. Pagination is a useful feature for handling large sets of data and improving the user experience. Feel free to customize the code to suit your specific requirements. Happy coding!