About

This package has been created with modularity in mind. You don't need to import any networking related code if you're planning on reading messages from stdout and shouting them at random strangers (or more conveniently using a radio module).

The core is written in ES5 to be able to run on very basic interpreters as long as they support Uint8Array (e.g. Espruino).

You are in charge of listening for the generated messages and sending them to an interface.

This is made easier by the included adapters:

• espruino-tcp
• espruino-udp

Usage

Install using npm:

$ npm install nano-mqtt

Node.js

const nanoMQTT = require('nano-mqtt');

const nano = new nanoMQTT('device-uuid');

Espruino TCP

const nanoMQTT = require('nano-mqtt/lib');
const nanoTCP = require('nano-mqtt/lib/adapter/espruino-tcp');

const nano = nanoTCP(
	new nanoMQTT('device-uuid'),
	'192.168.0.1',
	1883,
	10000, // connection timeout
	5000, // retry delay
);

Espruino UDP

Basic usage with a UDP broker

const nanoMQTT = require('nano-mqtt/lib');
const nanoUDP = require('nano-mqtt/lib/adapter/espruino-udp');

const nano = nanoUDP(
	new nanoMQTT('device-uuid'),
	'192.168.0.1',
	1883,
);

UDP mesh without broker

const nanoMQTT = require('nano-mqtt/lib');
const nanoUDP = require('nano-mqtt/lib/adapter/espruino-udp');

const nano = nanoUDP(
	new nanoMQTT('device-uuid'),
	'192.168.0.255',
	1883,
	1883,
);

API

Event: 'connected'

Emitted after receiving a CONNACK packet or setConnected was called with true.

nano.on('connected', () => {
	console.log('we are connected to broker');
});

Event: 'disconnected'

Emitted after setConnected was called with false.

nano.on('disconnected', () => {
	console.log('we have been disconnected from broker');
});

Event: 'message'

Emitted after receiving a PUBLISH packet.

• topic <string>
• payload <string>

nano.on('message', (topic, payload) => {
	console.log('received message', topic, payload);
});

Event: 'data'

Emitted when a packet has been generated and is ready to be sent.

• packet <Uint8Array>
• type <number>

nano.on('data', (packet, type) => {
	console.log('packet has been generated');
	socket.send(packet);
});

Event: 'error'

Emitted when trying to parse an unknown packet.

• packet <Uint8Array>

nano.on('error', (packet) => {
	console.log('unknown packet', packet);
});

setConnected(isConnected)

• isConnected <boolean>

Sets the connection status and emits the corresponding event (connected or disconnected).

connect()

Generates and emits a CONNECT packet.

disconnect()

Generates and emits a DISCONNECT packet.

publish(topic, payload, retain)

• topic <string>
• payload <string>
• retain <boolean>

Generates and emits a PUBLISH packet. Retain is false by default.

subscribe(topic)

• topic <string>

Generates and emits a SUBSCRIBE packet.

parse(data)

• data <Uint8Array>

Parses data packet and emits the corresponding event, or error on unknown packet type. The parsed packet is returned in the format of [PACKET_INT_TYPE, ...value]