MQTT messages/second

message_rate.js

const mqtt = require('mqtt');
const client = mqtt.connect('mqtt://iot.eclipse.org');

let start = null,
    count = 0,
    topicAverage = 0,
    payloadAverage = 0;

const topics = [],
    payloads = [];

client.on('connect', () => {
    client.subscribe('#');
});

client.on('message', (topic, message) => {
    if (start === null) {
        start = new Date();
    }
    count++;
    topics.push(Buffer.byteLength(topic.toString(), 'utf8'));
    payloads.push(Buffer.byteLength(message.toString(), 'utf8'));

    const end = new Date();
    if (end.getTime() - start.getTime() >= 1000) {
        client.unsubscribe('#');

        topics.forEach(topic => {
            topicAverage += topic;
        });
        topicAverage = topicAverage / topics.length;

        payloads.forEach(payload => {
            payloadAverage += payload;
        });
        payloadAverage = payloadAverage / payloads.length;

        console.log(`Messages: ${count}`);
        console.log(`Average topic size: ${topicAverage} bytes`);
        console.log(`Average payload size: ${payloadAverage} bytes`);
        console.log(`Date size: ${Buffer.byteLength(start.toJSON(), 'utf8')} bytes`);
        console.log(`Total time ${(end.getTime() - start.getTime())/1000} seconds`);
        process.exit()
    }
});