mqtt 3.0.0

MQTT.js is a client library specifically designed for the MQTT protocol. Written in JavaScript, it's ideal for Node.js and browser environments. MQTT (Message Queuing Telemetry Transport) is a lightweight, publish-subscribe messaging protocol usually used for machine-to-machine (M2M) or Internet of Things applications where bandwidth and resource constraints often exist.

To use MQTT.js, you must first install the package using npm with the following command: npm install mqtt --save. Once installed, you can require it in your JavaScript file and use its functions to connect to a broker and publish or subscribe to topics. To give an example, the below code connects to a broker and publishes a message:

const mqtt = require("mqtt");
const client = mqtt.connect("mqtt://broker-url");

client.on("connect", () => {
  client.publish("topic-name", "Hello mqtt");
  client.end();
});

In this example, replace "mqtt://broker-url" with the URL of your MQTT broker, and "topic-name" with the name of your topic. The message "Hello mqtt" is published to this topic.

The documentation for the MQTT.js library can be found within its GitHub repository at https://github.com/mqttjs/MQTT.js. Here, you'll find details about the library's API, examples of how to use it, and other information, such as its upgrade notes, command line tools, and browser support.