Node.js Http2ServerResponse.write() Method

Last Updated : 4 Aug, 2026

The Http2ServerResponse.write() method in Node.js writes a chunk of data to the response body. It allows data to be sent to the client before the response is ended.

  • It writes a data chunk to the response.
  • It can be called multiple times before end().
  • It is useful for sending data in multiple chunks.

Syntax:

response.write(chunk[, encoding][, callback]);

Parameters: This method accepts the following argument as a parameter.

  • response: The Http2ServerResponse object used to send the HTTP/2 response to the client.
  • chunk: The data to write to the response body. It can be a string, Buffer, Uint8Array, or DataView.
  • encoding (optional): The character encoding to use when chunk is a string (for example, 'utf8').
  • callback (optional): A function that is called after the data has been flushed to the stream.

Return Value: The response.write() method returns a boolean:

  • true: The data was accepted for writing.
  • false: The internal buffer is full, so wait for the 'drain' event before writing more data.

Example 1:

JavaScript 
const http2 = require('http2');
const fs = require('fs');

// Private key and public certificate for access
const options = {
    key: fs.readFileSync('private-key.pem'),
    cert: fs.readFileSync('public-cert.pem'),
};

// Request and response handler
const http2Handlers = (request, response) => {

    // Sending the data to the client
    // by using response.write() method
    response.write("hi")

    // Sending the signal to client
    response.end("hello world")
};

// Creating and initializing server
// by using http2.createServer() method
const server = http2.createServer(options, http2Handlers);

server.on('stream', (stream, requestheader) => {
    stream.write('hello ');

    // Getting all information of this http2stream object
    // by using state method
    const status = stream.state;

    stream.end("priority weight : " + status.weight);

    // Stopping the server
    // by using the close() method
    server.close(() => {
        console.log("server destroyed");
    })
});

server.listen(8000);

// Creating and initializing client
// by using tls.connect() method
const client = http2.connect('http://localhost:8000');

const req = client.request({ ':method': 'GET', ':path': '/' });

req.on('response', (responsesocket) => {
    console.log("status : " + responsesocket[":status"]);
});

req.on('data', (data) => {
    console.log('Received: %s ',
    data.toString().replace(/(\n)/gm, ""));
});

req.on('end', () => {
    client.close(() => {
        console.log("client destroyed");
    })
});

Output:

status : 200
Received: hi
Received: hello world
client destroyed
server destroyed

Example 2:

JavaScript 
const http2 = require('http2');
const fs = require('fs');

// Private key and public certificate for access
const options = {
    key: fs.readFileSync('private-key.pem'),
    cert: fs.readFileSync('public-cert.pem'),
};

// Request and response handler
const http2Handlers = (request, response) => {
    
    // Sending the data to the client
    // by using response.write() method
    response.write("GeeksForGeeks")
};

// Creating and initializing server
// by using http2.createServer() method
const server = http2.createServer(options, http2Handlers);

server.on('stream', (stream, requestHeaders) => {

    // Getting all information of this http2stream object
    // by using state method
    const status = stream.state;

    stream.end("The sum weight of all Http2Stream : " + 
    status.sumDependencyWeight);

    // Stopping the server
    // by using the close() method
    server.close(() => {
        console.log("server destroyed");
    })
});

server.listen(8000);

// Creating and initializing client
// by using tls.connect() method
const client = http2.connect('http://localhost:8000');

const req = client.request({ ':method': 'GET', 
':path': '/www.geeksforgeeks.org' });

req.on('data', (data) => {
    console.log('Received: %s ',
    data.toString().replace(/(\n)/gm, ""));
});

req.on('end', () => {
    client.close(() => {
        console.log("client destroyed");
    })
});

Output:

Received: GeeksForGeeks
Received: The sum weight of all Http2Stream : 0
client destroyed
server destroyed

Use Cases of Http2ServerResponse.write() Method

  • Sending response data to the client in chunks.
  • Streaming large files or generated content.
  • Sending data before the entire response is ready.
  • Building efficient HTTP/2 streaming applications.

Reference: https://nodejs.org/dist/latest-v12.x/docs/api/http2.html#http2_response_write_chunk_encoding_callback

Comment

Explore