mqtt test.js

var mqtt = require('mqtt');

var client = mqtt.connect('mqtt://localhost:1883', {
  username: "admin",
  password: "eyJhbGciOiJIUzUxMiJ9.eyJjcmVhdGVkIjoxNDc3NDg1NDc5OTEzLCJleHAiOjE0Nzc0ODcyNzksInV1aWQiOiI2NmVkNDc3Mi0wNDg5LTRlOTYtYmI2NS01NDhiMmVkMmM3MWQifQ.LbOAr8pPApDlVBLi32JWtCjmCa80ByAJYq9BnTnWQgh4SWka4WzykMU0D_atE5tYtgICj2QOg-OFglv2ZqLLNw",
  protocolId: 'MQTT',
  protocolVersion: 4,
});

client.on('connect', function () {
  console.log('connected');
  client.subscribe("foobar/#");
});

client.on("close", function () {
  console.log("disconnected");
});

client.on("error", function (err) {
  console.log("error: %j", err);
});

var i = 0;
client.on('message', function (topic, message) {
  console.log("\n%s) %s : %s", i, topic, message.toString());
  i++;
});