node_simple_sse.js

import express from 'express';
import SSE from 'sse';

let app = express();
app.use('/', (req, res) => {
    res.status(200).send('');
});

app.listen(3000, (err) => {
    if(err) throw err;
    let sse = new SSE(app);
    // jika ada koneksi klien
    sse.on('connection', (client) => {
        let isActive = true;
        // client bisa emit data, client.send('string')
        const sendInterval = () => {
            setTimeout(() => {
                client.send(JSON.stringify({message: 'halooo 😜'}));
                
                if(isActive) sendInterval();
            }, 2000)
        }

        client.on('close', () => {
            // stop interval
            isActive = false;
        })
    })
})