const zmq = require('/usr/local/lib/node_modules/zmq');

sub =  zmq.socket('sub');

//subscribe to only cat topic
sub.subscribe("cat");

sub.on('message' , function(topic , data) {

    let msg = JSON.parse(data),
    date = new Date(msg.time);

    console.log( topic + ' file has got change : ' + date);
});

sub.connect('tcp://localhost:3000');