Node.js socket.bind() Method

The socket.bind() method is an inbuilt application programming interface of class Socket within dgram module which is used to bind the particular data gram server to a particular port with some required information.

Syntax:

const socket.bind(options[, callback])

Parameters: This method takes the following parameter:

• option: It can use the following parameters- 
  • port: port value.
  • address: address
  • exclusive: Boolean value true or false.
  • fd: Integer value.
• callback: Callback function for further operation.

Return Value: This method returns the object which contains the address information for the socket.

Example 1: In this example, we will see the use of socket.bind() method.

Filename: index.js

Javascript

// Node.js program to demonstrate the
// server.bind() method

// Importing dgram module
const dgram = require('dgram');

// Creating and initializing client
// and server socket
let client = dgram.createSocket("udp4");
let server = dgram.createSocket("udp4");

// Catching the message event
server.on("message", function (msg) {

    // Displaying the client message
    process.stdout.write("UDP String: " + msg + "\n");

    // Exiting process
    process.exit();
})
    // Binding server with port
    .bind(1234, () => {

        // Getting the address information
        // for the server by using
        // address() method
        const address = server.address()

        // Display the result
        console.log(address);

    });

// Client sending message to server
client.send("Hello", 0, 7, 1234, "localhost");

Output:

{ address: '0.0.0.0', family: 'IPv4', port: 1234 }
UDP String: Hello

Example 2: In this example, we will see the use of socket.bind() method.

Filename: index.js

Javascript

// Node.js program to demonstrate the
// server.bind() method

// Importing dgram module
const dgram = require('dgram');

// Creating and initializing client
// and server socket
let client = dgram.createSocket("udp4");
let server = dgram.createSocket("udp4");

// Catching the message event
server.on("message", function (msg) {

    // Displaying the client message
    process.stdout.write("UDP String: " + msg + "\n");

    // Exiting process
    process.exit();

});

// Catching the listening event
server.on('listening', () => {

    // Getting address information for the server
    const address = server.address();

    // Display the result
    console.log(`server listening
        ${address.address}:${address.port}`);
});

// Binding server with port address
// by using bind() method
server.bind(1234, () => {

    // Adding a multicast address for others to join
    server.addMembership('224.0.0.114');
});

// Client sending message to server
client.send("Hello", 0, 7, 1234, "localhost");

Output:

server listening 0.0.0.0:1234
UDP String: Hello

Run the index.js file using the following command:

node index.js

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