Instead of on('message', messageHandler), you should write onmessage = messageHandler. Note that WebSockets in the browser have slightly different syntax for waiting for the connection and receiving messages from the server. Server.on( 'connection', function( socket) `

You can think of this as a simple chat server: when one person sends a message, the server broadcasts the message to everyone listening. How to use WebSockets with Node. initializes node and creates a package.json file. Now fire up the node terminal and go to the server directory and run the following commands one by one. You can also use Socket.IO, but Socket.IO is a higher level framework on top of WebSockets rather than an implementation of the WebSocket protocol.īelow is a basic example of a WebSocket server that tracks all open sockets and sends inbound messages to all open sockets. First, in our project folder create two folders named client and server. The ws npm package is the de facto WebSocket library for Node.js. In this article, you'll learn how to build a simple real-time chat application using WebSockets. WebSockets put more of a burden on the developer, so use them sparingly and only when you absolutely need them. WebSockets are more flexible, but also are harder to implement and scale. This is different from your standard HTTP request using fetch() or Axios because the server cannot communicate with the client unless the client sends a request first.

In particular, WebSockets enable the server to push data to the client. WebSockets are a tool for bidirectional communication between a browser client and a server.

Node js websocket example