mqtt-packet

{
  cmd: 'connect',
  protocolId: 'MQTT', // Or 'MQIsdp' in MQTT 3.1 and 5.0
  protocolVersion: 4, // Or 3 in MQTT 3.1, or 5 in MQTT 5.0
  clean: true, // Can also be false
  clientId: 'my-device',
  keepalive: 0, // Seconds which can be any positive number, with 0 as the default setting
  username: 'matteo',
  password: Buffer.from('collina'), // Passwords are buffers
  will: {
    topic: 'mydevice/status',
    payload: Buffer.from('dead'), // Payloads are buffers
    properties: { // MQTT 5.0
      willDelayInterval: 1234,
      payloadFormatIndicator: false,
      messageExpiryInterval: 4321,
      contentType: 'test',
      responseTopic: 'topic',
      correlationData: Buffer.from([1, 2, 3, 4]),
      userProperties: {
        'test': 'test'
      }
    }
  },
  properties: { // MQTT 5.0 properties
      sessionExpiryInterval: 1234,
      receiveMaximum: 432,
      maximumPacketSize: 100,
      topicAliasMaximum: 456,
      requestResponseInformation: true,
      requestProblemInformation: true,
      userProperties: {
        'test': 'test'
      },
      authenticationMethod: 'test',
      authenticationData: Buffer.from([1, 2, 3, 4])
  }
}

If protocolVersion is 3, clientId is mandatory and generate will throw if
missing.

If password or will.payload are passed as strings, they will
automatically be converted into a Buffer.

Connack

{
  cmd: 'connack',
  returnCode: 0, // Or whatever else you see fit MQTT < 5.0
  sessionPresent: false, // Can also be true.
  reasonCode: 0, // reason code MQTT 5.0
  properties: { // MQTT 5.0 properties
      sessionExpiryInterval: 1234,
      receiveMaximum: 432,
      maximumQoS: 2,
      retainAvailable: true,
      maximumPacketSize: 100,
      assignedClientIdentifier: 'test',
      topicAliasMaximum: 456,
      reasonString: 'test',
      userProperties: {
        'test': 'test'
      },
      wildcardSubscriptionAvailable: true,
      subscriptionIdentifiersAvailable: true,
      sharedSubscriptionAvailable: false,
      serverKeepAlive: 1234,
      responseInformation: 'test',
      serverReference: 'test',
      authenticationMethod: 'test',
      authenticationData: Buffer.from([1, 2, 3, 4])
  }
}

The only mandatory argument is returnCode, as generate will throw if
missing.

Subscribe

{
  cmd: 'subscribe',
  messageId: 42,
  properties: { // MQTT 5.0 properties
    subscriptionIdentifier: 145,
    userProperties: {
      test: 'test'
    }
  }
  subscriptions: [{
    topic: 'test',
    qos: 0,
    nl: false, // no Local MQTT 5.0 flag
    rap: true, // Retain as Published MQTT 5.0 flag
    rh: 1 // Retain Handling MQTT 5.0
  }]
}

All properties are mandatory.

Suback

{
  cmd: 'suback',
  messageId: 42,
  properties: { // MQTT 5.0 properties
    reasonString: 'test',
    userProperties: {
      'test': 'test'
    }
  }
  granted: [0, 1, 2, 128]
}

All the granted qos must be < 256, as they are encoded as UInt8.
All properties are mandatory.

Unsubscribe

{
  cmd: 'unsubscribe',
  messageId: 42,
  properties: { // MQTT 5.0 properties
    userProperties: {
      'test': 'test'
    }
  }
  unsubscriptions: [
    'test',
    'a/topic'
  ]
}

All properties are mandatory.

Unsuback

{
  cmd: 'unsuback',
  messageId: 42,
  properties: { // MQTT 5.0 properties
    reasonString: 'test',
    userProperties: {
      'test': 'test'
    }
  }
}

All properties are mandatory.

Publish

{
  cmd: 'publish',
  messageId: 42,
  qos: 2,
  dup: false,
  topic: 'test',
  payload: Buffer.from('test'),
  retain: false,
  properties: { // optional properties MQTT 5.0
      payloadFormatIndicator: true,
      messageExpiryInterval: 4321,
      topicAlias: 100,
      responseTopic: 'topic',
      correlationData: Buffer.from([1, 2, 3, 4]),
      userProperties: {
        'test': 'test'
      },
      subscriptionIdentifier: 120, // can be an Array in message from broker, if message included in few another subscriptions
      contentType: 'test'
   }
}

Only the topic property is mandatory.
Both topic and payload can be Buffer objects instead of strings.
messageId is mandatory for qos > 0.

Puback

{
  cmd: 'puback',
  messageId: 42,
  reasonCode: 16, // only for MQTT 5.0
  properties: { // MQTT 5.0 properties
      reasonString: 'test',
      userProperties: {
        'test': 'test'
      }
  }
}

The only mandatory property is messageId, as generate will throw if
missing.

Pubrec

{
  cmd: 'pubrec',
  messageId: 42,
  reasonCode: 16, // only for MQTT 5.0
  properties: { // properties MQTT 5.0
    reasonString: 'test',
    userProperties: {
      'test': 'test'
    }
  }
}

The only mandatory property is messageId, as generate will throw if
missing.

Pubrel

{
  cmd: 'pubrel',
  messageId: 42,
  reasonCode: 16, // only for MQTT 5.0
  properties: { // properties MQTT 5.0
     reasonString: 'test',
     userProperties: {
       'test': 'test'
     }
  }
}

The only mandatory property is messageId, as generate will throw if
missing.

Pubcomp

{
  cmd: 'pubcomp',
  messageId: 42,
  reasonCode: 16, // only for MQTT 5.0
  properties: { // properties MQTT 5.0
    reasonString: 'test',
    userProperties: {
       'test': 'test'
    }
  }
}

The only mandatory property is messageId, as generate will throw if
missing.

Pingreq

{
  cmd: 'pingreq'
}

Pingresp

{
  cmd: 'pingresp'
}

Disconnect

{
  cmd: 'disconnect',
  reasonCode: 0, // MQTT 5.0 code
  properties: { // properties MQTT 5.0
     sessionExpiryInterval: 145,
     reasonString: 'test',
     userProperties: {
       'test': 'test'
     },
     serverReference: 'test'
  }
}

Auth

{
  cmd: 'auth',
  reasonCode: 0, // MQTT 5.0 code
  properties: { // properties MQTT 5.0
     authenticationMethod: 'test',
     authenticationData: Buffer.from([0, 1, 2, 3]),
     reasonString: 'test',
     userProperties: {
       'test': 'test'
     }
  }
}