How to use Websockets in Node.js?

WebSockets provide a powerful way to enable bidirectional communication between the client and the server. This means, unlike HTTP communication, the server can also initiate communication with the client without explicitly waiting for a request. This feature makes it perfect for use in applications that require real-time data updates such as chat applications, realtime games, analytic trackers, etc.

Here’s a simplified example of how to use it in node.js.

1. First we need to install WebSocket module by running `npm install ws` in the terminal.

1. Now let’s create a simple WebSocket server:

```
const WebSocket = require(‘ws’);

// Create a new WebSocket Server
const server = new WebSocket.Server({ port: 8080 });

// Connection event. This will be emitted when a client connects
server.on(‘connection’, (socket) => { console.log(‘Client connected’);

// Listen for messages from clients socket.on(‘message’, (message) => { console.log(‘Received: ‘ + message); }); // Send a message to the client socket.send(‘Hello from Server!’); }); ```

1. Now, let’s create a simple WebSocket client.

```
const WebSocket = require(‘ws’);

// Connect to WebSocket server
const socket = new WebSocket(‘ws://localhost:8080’);

socket.on(‘open’, function() { console.log(‘Connected to server’);

// Send a message to the server socket.send(‘Hello from Client!’); });

// Listen for messages from the server
socket.on(‘message’, function(message) { console.log(‘Received: ‘ + message);
});
```

In this example:

- A connection is made to the WebSocket server when a new ‘WebSocket’ object is created with the `new WebSocket(url)` syntax.
- The ‘message’ event listener is set up to respond to any messages that come from the server.
- A message is sent to the server on connection by using the `socket.send()` function.