eventsource-client

import { createEventSource } from 'eventsource-client'; async function connectToSSE() { const sseUrl = 'https://my-server.com/sse'; // Replace with your SSE endpoint const es = createEventSource({ url: sseUrl, // Optional: provide a custom fetch implementation if needed, e.g., for Node.js < 18 or specific proxying. // fetch: customFetchFunction, onMessage: ({ data, event, id }) => { console.log(`Received Event - ID: ${id ?? 'N/A'}, Event: ${event ?? 'message'}, Data: ${data}`); }, onOpen: () => { console.log('SSE connection opened.'); }, onDisconnect: () => { console.log('SSE connection disconnected.'); }, onError: (err) => { console.error('SSE Error:', err); } }); // You can also use the async iterator pattern: // for await (const { data } of es) { // console.log('Data (from iterator): %s', data); // // You might want to break out of this loop based on some condition // // and call es.close() manually. // } console.log('Current readyState:', es.readyState); console.log('Last Event ID:', es.lastEventId); // To prevent indefinite connection or reconnects, call close() when done. // For demonstration, let's close after 10 seconds if still open. setTimeout(() => { if (es.readyState !== 'closed') { console.log('Closing SSE connection after timeout.'); es.close(); } }, 10000); } connectToSSE().catch(console.error);