eventsource

Connecting to an SSE server

This code demonstrates how to connect to an SSE server and listen for messages. The 'onmessage' handler is called whenever a new message is received, and the 'onerror' handler is called if there's an error with the connection.

const EventSource = require('eventsource');
const es = new EventSource('http://example.com/events');
es.onmessage = function(event) {
  console.log(event.data);
};
es.onerror = function(err) {
  console.error('EventSource failed:', err);
};

Listening for specific event types

This code snippet shows how to listen for specific event types using the 'addEventListener' method. In this example, the client listens for 'userupdate' events and processes the received data.

const EventSource = require('eventsource');
const es = new EventSource('http://example.com/events');
es.addEventListener('userupdate', function(event) {
  const userData = JSON.parse(event.data);
  console.log('User update:', userData);
});

Reconnecting after connection loss

This example illustrates the automatic reconnection feature of the EventSource API. The 'onopen' handler is called when the connection is successfully established, and the 'onerror' handler indicates that the connection has been lost and a reconnection attempt will be made.

const EventSource = require('eventsource');
const es = new EventSource('http://example.com/events');
es.onopen = function() {
  console.log('Connection to server opened.');
};
es.onerror = function() {
  console.log('Connection lost, the browser will automatically attempt to reconnect.');
};