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Onelinerhub
Onelinerhub

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Creating Websocket servers and clients in Nodejs

1. Websocket server example

const WebSocketServer = require('ws');
const wss = new WebSocketServer.Server({ port: 8111 })

wss.on("connection", (ws,r) => {
  ws.on("message", data => {
    ws.send('You sent me: ' + data);
  });

  ws.on("close", () => { });
  ws.onerror = function () { };
});
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  • require('ws') - import ws lib to create websocket server,
  • new WebSocketServer.Server - create and launch websocket server with params,
  • port: - port to listen on (in our case all network interfaces are going to be listened),
  • wss.on("connection" - what to do when someone connects to our server,
  • ws.on("message" - what to do when we've received a message from client,
  • ws.send( - send a message to client,
  • ws.on("close" - what to do when client closes connection,
  • ws.onerror - set custom error handler.

Open original or edit on Github.

2. Websocket client example

let ws = require('websocket');
let wsc = new ws.client;

wsc.on('connect', function(connection) {
  connection.sendUTF('Hello');

  connection.on('message', function(message) {
    console.log("Received: " + message.utf8Data);
    // connection.close();
  });
});

wsc.connect('ws://echoof.me:8111/');
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  • require('websocket') - import websocket lib to create websocket client,
  • new ws.client - create new websocket client object,
  • wsc.on('connect' - specify what to do when client gets connected to websocket server,
  • connection.sendUTF - send message to server,
  • connection.on('message' - specify what to do when client received message from server,
  • connection.close() - close connection (and exit),
  • wsc.connect - connect to websocket server,
  • echoof.me:8111 - public echo websocket server.

Open original or edit on Github.

Oldest comments (0)

Classic DEV Post from 2020:

js visualized

🚀⚙️ JavaScript Visualized: the JavaScript Engine

As JavaScript devs, we usually don't have to deal with compilers ourselves. However, it's definitely good to know the basics of the JavaScript engine and see how it handles our human-friendly JS code, and turns it into something machines understand! 🥳

Happy coding!