RabbitMQ nodejs example message ack

publisher.js

var amqp = require('amqp'),
    C = require('config'),
    config = C.server,
    connection;

connection = amqp.createConnection({
    url: config.rabbitmq.url
});

connection.on('ready', function() {
    console.log('Ready');
    connection.queue('task_queue', {
        autoDelete: false,
        durable: true
    }, function(queue) {
        console.log('Task queue');

        function queue(i) {
            var message = 'base_message' + ' ' + i;
            connection.publish('task_queue', message, {
                deliveryMode: 2
            });

            console.log(" [x] Sent %s", message);
            if (i < 30) {
                setTimeout(function() {
                    queue(i + 1);
                }, 700);
            }
        }

        queue(1);
    });
});

worker.js

var amqp = require('amqp'),
    C = require('config'),
    config = C.server,
    connection;

connection = amqp.createConnection({
    url: config.rabbitmq.url,
    clientProperties: {
        capabilities: {
            consumer_cancel_notify: false
        }
    }
});

function main(workerID) {
    var workerStr = workerID ? "W[" + workerID + "]" : "";

    connection.on('ready', function() {

        connection.queue('task_queue', {
            autoDelete: false,
            durable: true
        }, function(queue) {
            console.log('[*] Waiting for messages. To exit press CTRL+C');
            queue.subscribe({
                ack: true,
                prefetchCount: 1
            }, function(json, headers, info, message) {

                var body = json.data.toString('utf-8');
                console.log(" [*]%s Received %s", workerStr, body);
                setTimeout(function() {
                    var rnd = Math.floor((Math.random() * 3) + 1);
                    if (rnd == 2) {
                        console.log("   [x]%s Failed %s", workerStr, body);
                        message.reject(true);
                        //queue.shift(true, true); // NOT WORK: https://github.com/postwait/node-amqp/issues/210
                    } else {
                        console.log("   [√]%s Done %s", workerStr, body);
                        queue.shift(); // basic_ack equivalent
                    }
                }, 4000);
            });
        });
    });
}

main(2321321);