examples/server-sent-events/benchmark.js

const http = require('http')

const n = 120;
let connected = 0;
let messages = 0;
let start = Date.now();
let phase = 'connecting';
let connection_time;
let broadcast_time;

let message = process.argv[2] || 'msg';
let expected_data = "data: " + message;

for (let i = 0; i < n; i++) {
    http.get({
        host: '127.0.0.1',
        port: 8080,
        path: '/events'
    }, response => {
        response.on('data', data => {
            if (data.includes(expected_data)) {
                messages += 1;
            } else if (data.includes("data: connected\n")) {
                connected += 1;
            }
        })
    }).on('error', (_) => {});
}

setInterval(() => {
    if (phase === 'connecting' && connected === n) {
        // done connecting
        phase = 'messaging';
        connection_time = Date.now() - start;
    }

    if (phase === 'messaging') {
        phase = 'waiting';
        start = Date.now();

        http.get({
            host: '127.0.0.1',
            port: 8080,
            path: '/broadcast/' + message
        }, response => {
            response.on('data', _ => {})
        })
    }

    if (phase === 'waiting' && messages >= n) {
        // all messages received
        broadcast_time = Date.now() - start;
        phase = 'paused';
        messages = 0;
        phase = 'messaging';
    }

    process.stdout.write("\r\x1b[K");
    process.stdout.write(`Connected: ${connected}, connection time: ${connection_time} ms, total broadcast time: ${broadcast_time} ms`);
}, 20)