Is there experience working with WebSocket and long polling?

Yes, I have experience working with WebSocket and long polling.

WebSocket is a protocol that establishes a persistent, two-way connection between the client and the server. This allows the server to send data to the client in real-time without the need for constant requests from the client.

Long polling is a technique where the client sends a request to the server, and the server holds this request open until new data is available or a timeout occurs. After receiving the response, the client immediately sends a new request, ensuring almost continuous updates.

Example of using WebSocket in JavaScript:

const socket = new WebSocket('wss://example.com/socket');
socket.onopen = () => {
  console.log('Connection established');
  socket.send('Hello server!');
};
socket.onmessage = (event) => {
  console.log('Received message:', event.data);
};
socket.onclose = () => {
  console.log('Connection closed');
};

Simplified example of long polling:

function longPoll() {
  fetch('/long-poll-endpoint')
    .then(response => response.json())
    .then(data => {
      console.log('Data received:', data);
      longPoll(); // immediately send a new request
    })
    .catch(() => {
      setTimeout(longPoll, 5000); // retry after 5 seconds on error
    });
}
longPoll();