What is the main task solved by the Socket.IO library in applications?

Socket.IO library solves the problem of organizing two-way, persistent communication between the client and server in real time. It simplifies working with WebSocket and provides:

• Automatic switching between transports (WebSocket, long-polling, etc.) for maximum compatibility.
• A simple API for sending and receiving events.
• Support for rooms and namespaces for grouping clients.

Example of using Socket.IO on a Node.js server:

const io = require('socket.io')(3000);
io.on('connection', socket => {
  console.log('Client connected');
  socket.on('message', msg => {
    console.log('Message from client:', msg);
    socket.emit('reply', 'Received: ' + msg);
  });
});

Thus, Socket.IO allows creating chat applications, games, and other real-time updating applications.