@jsh/mqtt

Client

The MQTT client.

Usage example

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const mqtt = require("@jsh/mqtt");
const client = new mqtt.Client({ serverUrls: ["tcp://127.0.0.1:1236"] });
try {
    client.onConnect = connAck => { println("connected."); }
    client.onConnectError = err => { println("connect error", err); }
    client.connect({timeout: 10*1000});
    client.publish("test/topic", "Hello, MQTT!", 0)
} catch(e) {
    console.log("Error:", e);
} finally {
    client.disconnect({waitForEmptyQueue:true});
}

Creation

Options

connect()

Syntax

connect(opts)

Parameters

• opts Object

Return value

None.

disconnect()

Syntax

disconnect(opts)

Parameters

• opts Object

Return value

None.

subscribe()

Syntax

subscribe(opts)

Parameters

• opts Object SubscriptionOption

SubscriptionOption

Subscription

Properties

Return value

None.

Usage example

const topicName = 'sensor/temperature';
client.subscribe({subscriptions:[{topic:topicName, qos:0}]});

unsubscribe()

Syntax

unsubscribe(opts)

Parameters

• opts Object UnsubscribeOption

UnsubscribeOption

Properties

Return value

None.

Usage example

const topicName = 'sensor/temperature';
client.unsubscribe({topics:[topicName]});

publish()

Syntax

publish(opts, payload)

Parameters

• opts Object PublishOptions
• payload String or Number

PublishOptions

Return value

• Object

Usage example

let r = client.publish('sensor/temperature', 'Hello World', 1)
console.log(r.reasonCode)

onMessage callback

Callback function that receives a message.

Syntax

function (msg) { }

• msg Object Message

Message

Payload

• msg.payload.bytes()
• msg.payload.string()

Properties

onConnect callback

On connect callback.

Syntax

function (ack) { }

Parameters

• ack Object

Properties

Return value

None.

onConnectError callback

On connect error callback.

Syntax

function (err) { }

Parameters

• error String

Return value

None.

onDisconnect callback

On disconnect callback

Syntax

function (disconn) { }

Parameters

• disconn Object

Return value

None.

onClientError callback

On client error callback

Syntax

function (err) { }

Parameters

• err String

Return value

None.