What is chunk in Node.js ?

Last Updated : 25 Apr, 2022

The data is a transfer from server to client for a particular request in the form of a stream. The stream contains chunks. A chunk is a fragment of the data that is sent by the client to server all chunks concepts to each other to make a buffer of the stream then the buffer is converted into meaningful data. In this article, we will discuss how to send chunks from the request body to the server. The request object is used for handling the chunks of data.

Syntax:

request.on('eventName',callback)

Parameters: This function accepts the following two parameters:

eventName: It is the name of the event that fired
callback: It is the Callback function i.e Event handler of the particular event.

Return type: The return type of this method is void.

Example: Create an index.js file with the following code.

index.js

// Importing http libraries 
const http = require('http'); 
  
// Creating a server 
const server = http.createServer((req, res) => { 
    const url = req.url; 
    const method = req.method; 
  
    if (url === '/') { 
        // Sending the response 
        res.write('<html>'); 
        res.write('<head><title>Enter Message</title><head>'); 
        res.write(`<body><form action="/message" method="POST"> 
    <input type="text" name="message"></input> 
    <button type="submit">Send</button></form></body></html>`); 
        res.write('</html>'); 
        return res.end(); 
    } 
  
    // Handling different routes for different type request 
    if (url === '/message' && method === 'POST') { 
        const body = []; 
  
        req.on('data', (chunk) => { 
  
            // Storing the chunk data 
            body.push(chunk); 
            console.log(body) 
        }); 
  
        req.on('end', () => { 
  
            // Parsing the chunk data 
            const parsedBody = Buffer.concat(body).toString(); 
            const message = parsedBody.split('=')[1]; 
              
            // Printing the data 
            console.log(message); 
        }); 
  
        res.statusCode = 302; 
        res.setHeader('Location', '/'); 
        return res.end(); 
    } 
}); 
  
// Starting the server 
server.listen(3000); 