fix: 修复Message 导入

es/Message.js

+import { ERROR } from './consts';
+import { format, parseUTF8, stringToUTF8, UTF8Length } from './utils';
+/* eslint-disable */
+
+var Message = function Message(newPayload) {
+  var payload;
+
+  if (typeof newPayload === 'string' || newPayload instanceof ArrayBuffer || ArrayBuffer.isView(newPayload) && !(newPayload instanceof DataView)) {
+    payload = newPayload;
+  } else {
+    throw format(ERROR.INVALID_ARGUMENT, [newPayload, 'newPayload']);
+  }
+
+  var destinationName;
+  var qos = 0;
+  var retained = false;
+  var duplicate = false;
+  Object.defineProperties(this, {
+    payloadString: {
+      enumerable: true,
+      get: function get() {
+        if (typeof payload === 'string') return payload;else return parseUTF8(payload, 0, payload.length);
+      }
+    },
+    payloadBytes: {
+      enumerable: true,
+      get: function get() {
+        if (typeof payload === 'string') {
+          var buffer = new ArrayBuffer(UTF8Length(payload));
+          var byteStream = new Uint8Array(buffer);
+          stringToUTF8(payload, byteStream, 0);
+          return byteStream;
+        } else {
+          return payload;
+        }
+      }
+    },
+    destinationName: {
+      enumerable: true,
+      get: function get() {
+        return destinationName;
+      },
+      set: function set(newDestinationName) {
+        if (typeof newDestinationName === 'string') destinationName = newDestinationName;else throw new Error(format(ERROR.INVALID_ARGUMENT, [newDestinationName, 'newDestinationName']));
+      }
+    },
+    qos: {
+      enumerable: true,
+      get: function get() {
+        return qos;
+      },
+      set: function set(newQos) {
+        if (newQos === 0 || newQos === 1 || newQos === 2) qos = newQos;else throw new Error('Invalid argument:' + newQos);
+      }
+    },
+    retained: {
+      enumerable: true,
+      get: function get() {
+        return retained;
+      },
+      set: function set(newRetained) {
+        if (typeof newRetained === 'boolean') retained = newRetained;else throw new Error(format(ERROR.INVALID_ARGUMENT, [newRetained, 'newRetained']));
+      }
+    },
+    topic: {
+      enumerable: true,
+      get: function get() {
+        return destinationName;
+      },
+      set: function set(newTopic) {
+        destinationName = newTopic;
+      }
+    },
+    duplicate: {
+      enumerable: true,
+      get: function get() {
+        return duplicate;
+      },
+      set: function set(newDuplicate) {
+        duplicate = newDuplicate;
+      }
+    }
+  });
+};
+
+export default Message;
\ No newline at end of file

es/Pinger.js

+import { ERROR, MESSAGE_TYPE } from './consts';
+import { format } from './utils';
+import WireMessage from './WireMessage';
+/* eslint-disable */
+
+var Pinger = function Pinger(client, keepAliveInterval) {
+  this._client = client;
+  this._keepAliveInterval = keepAliveInterval * 1000;
+  this.isReset = false;
+  var pingReq = new WireMessage(MESSAGE_TYPE.PINGREQ).encode();
+
+  var doTimeout = function doTimeout(pinger) {
+    return function () {
+      return doPing.apply(pinger);
+    };
+  };
+  /** @ignore */
+
+
+  var doPing = function doPing() {
+    if (!this.isReset) {
+      this._client._trace("Pinger.doPing", "Timed out");
+
+      this._client._disconnected(ERROR.PING_TIMEOUT.code, format(ERROR.PING_TIMEOUT));
+    } else {
+      this.isReset = false;
+
+      this._client._trace("Pinger.doPing", "send PINGREQ");
+
+      this._client.socket.send(pingReq);
+
+      this.timeout = setTimeout(doTimeout(this), this._keepAliveInterval);
+    }
+  };
+
+  this.reset = function () {
+    this.isReset = true;
+    clearTimeout(this.timeout);
+    if (this._keepAliveInterval > 0) this.timeout = setTimeout(doTimeout(this), this._keepAliveInterval);
+  };
+
+  this.cancel = function () {
+    clearTimeout(this.timeout);
+  };
+};
+
+export default Pinger;
\ No newline at end of file

es/WireMessage.js

+import { MESSAGE_TYPE, MqttProtoIdentifierv3, MqttProtoIdentifierv4 } from './consts';
+import { encodeMBI, UTF8Length, writeString, writeUint16 } from './utils';
+/* eslint-disable */
+// interface WireMessageOptions {
+//     messageIdentifier?: number
+//     mqttVersion?: 3 | 4
+//     clientId?: string
+//     willMessage?: MqttMessage
+//     userName?: string
+//     password?: string
+//     topics?: string[]
+//     requestedQos?: (0 | 1 | 2)[]
+//     payloadMessage?: MqttMessage
+//     cleanSession?: boolean
+//     keepAliveInterval?: number
+//     [key: string]: any
+//   }
+
+var WireMessage = function WireMessage(type, options) {
+  this.type = type;
+
+  for (var name in options) {
+    if (options.hasOwnProperty(name)) {
+      this[name] = options[name];
+    }
+  }
+};
+
+WireMessage.prototype.encode = function () {
+  // Compute the first byte of the fixed header
+  var first = (this.type & 0x0f) << 4;
+  /*
+  * Now calculate the length of the variable header + payload by adding up the lengths
+  * of all the component parts
+  */
+
+  var remLength = 0;
+  var topicStrLength = [];
+  var destinationNameLength = 0;
+  var willMessagePayloadBytes; // if the message contains a messageIdentifier then we need two bytes for that
+
+  if (this.messageIdentifier !== undefined) remLength += 2;
+
+  switch (this.type) {
+    // If this a Connect then we need to include 12 bytes for its header
+    case MESSAGE_TYPE.CONNECT:
+      switch (this.mqttVersion) {
+        case 3:
+          remLength += MqttProtoIdentifierv3.length + 3;
+          break;
+
+        case 4:
+          remLength += MqttProtoIdentifierv4.length + 3;
+          break;
+      }
+
+      remLength += UTF8Length(this.clientId) + 2;
+
+      if (this.willMessage !== undefined) {
+        remLength += UTF8Length(this.willMessage.destinationName) + 2; // Will message is always a string, sent as UTF-8 characters with a preceding length.
+
+        willMessagePayloadBytes = this.willMessage.payloadBytes;
+        if (!(willMessagePayloadBytes instanceof Uint8Array)) willMessagePayloadBytes = new Uint8Array(payloadBytes);
+        remLength += willMessagePayloadBytes.byteLength + 2;
+      }
+
+      if (this.userName !== undefined) remLength += UTF8Length(this.userName) + 2;
+      if (this.password !== undefined) remLength += UTF8Length(this.password) + 2;
+      break;
+    // Subscribe, Unsubscribe can both contain topic strings
+
+    case MESSAGE_TYPE.SUBSCRIBE:
+      first |= 0x02; // Qos = 1;
+
+      for (var i = 0; i < this.topics.length; i++) {
+        topicStrLength[i] = UTF8Length(this.topics[i]);
+        remLength += topicStrLength[i] + 2;
+      }
+
+      remLength += this.requestedQos.length; // 1 byte for each topic's Qos
+      // QoS on Subscribe only
+
+      break;
+
+    case MESSAGE_TYPE.UNSUBSCRIBE:
+      first |= 0x02; // Qos = 1;
+
+      for (var i = 0; i < this.topics.length; i++) {
+        topicStrLength[i] = UTF8Length(this.topics[i]);
+        remLength += topicStrLength[i] + 2;
+      }
+
+      break;
+
+    case MESSAGE_TYPE.PUBREL:
+      first |= 0x02; // Qos = 1;
+
+      break;
+
+    case MESSAGE_TYPE.PUBLISH:
+      if (this.payloadMessage.duplicate) first |= 0x08;
+      first = first |= this.payloadMessage.qos << 1;
+      if (this.payloadMessage.retained) first |= 0x01;
+      destinationNameLength = UTF8Length(this.payloadMessage.destinationName);
+      remLength += destinationNameLength + 2;
+      var payloadBytes = this.payloadMessage.payloadBytes;
+      remLength += payloadBytes.byteLength;
+      if (payloadBytes instanceof ArrayBuffer) payloadBytes = new Uint8Array(payloadBytes);else if (!(payloadBytes instanceof Uint8Array)) payloadBytes = new Uint8Array(payloadBytes.buffer);
+      break;
+
+    case MESSAGE_TYPE.DISCONNECT:
+      break;
+
+    default:
+      break;
+  } // Now we can allocate a buffer for the message
+
+
+  var mbi = encodeMBI(remLength); // Convert the length to MQTT MBI format
+
+  var pos = mbi.length + 1; // Offset of start of variable header
+
+  var buffer = new ArrayBuffer(remLength + pos);
+  var byteStream = new Uint8Array(buffer); // view it as a sequence of bytes
+  //Write the fixed header into the buffer
+
+  byteStream[0] = first;
+  byteStream.set(mbi, 1); // If this is a PUBLISH then the variable header starts with a topic
+
+  if (this.type == MESSAGE_TYPE.PUBLISH) pos = writeString(this.payloadMessage.destinationName, destinationNameLength, byteStream, pos); // If this is a CONNECT then the variable header contains the protocol name/version, flags and keepalive time
+  else if (this.type == MESSAGE_TYPE.CONNECT) {
+    switch (this.mqttVersion) {
+      case 3:
+        byteStream.set(MqttProtoIdentifierv3, pos);
+        pos += MqttProtoIdentifierv3.length;
+        break;
+
+      case 4:
+        byteStream.set(MqttProtoIdentifierv4, pos);
+        pos += MqttProtoIdentifierv4.length;
+        break;
+    }
+
+    var connectFlags = 0;
+    if (this.cleanSession) connectFlags = 0x02;
+
+    if (this.willMessage !== undefined) {
+      connectFlags |= 0x04;
+      connectFlags |= this.willMessage.qos << 3;
+
+      if (this.willMessage.retained) {
+        connectFlags |= 0x20;
+      }
+    }
+
+    if (this.userName !== undefined) connectFlags |= 0x80;
+    if (this.password !== undefined) connectFlags |= 0x40;
+    byteStream[pos++] = connectFlags;
+    pos = writeUint16(this.keepAliveInterval, byteStream, pos);
+  } // Output the messageIdentifier - if there is one
+
+  if (this.messageIdentifier !== undefined) pos = writeUint16(this.messageIdentifier, byteStream, pos);
+
+  switch (this.type) {
+    case MESSAGE_TYPE.CONNECT:
+      pos = writeString(this.clientId, UTF8Length(this.clientId), byteStream, pos);
+
+      if (this.willMessage !== undefined) {
+        pos = writeString(this.willMessage.destinationName, UTF8Length(this.willMessage.destinationName), byteStream, pos);
+        pos = writeUint16(willMessagePayloadBytes.byteLength, byteStream, pos);
+        byteStream.set(willMessagePayloadBytes, pos);
+        pos += willMessagePayloadBytes.byteLength;
+      }
+
+      if (this.userName !== undefined) pos = writeString(this.userName, UTF8Length(this.userName), byteStream, pos);
+      if (this.password !== undefined) pos = writeString(this.password, UTF8Length(this.password), byteStream, pos);
+      break;
+
+    case MESSAGE_TYPE.PUBLISH:
+      // PUBLISH has a text or binary payload, if text do not add a 2 byte length field, just the UTF characters.
+      byteStream.set(payloadBytes, pos);
+      break;
+    //    	    case MESSAGE_TYPE.PUBREC:
+    //    	    case MESSAGE_TYPE.PUBREL:
+    //    	    case MESSAGE_TYPE.PUBCOMP:
+    //    	    	break;
+
+    case MESSAGE_TYPE.SUBSCRIBE:
+      // SUBSCRIBE has a list of topic strings and request QoS
+      for (var i = 0; i < this.topics.length; i++) {
+        pos = writeString(this.topics[i], topicStrLength[i], byteStream, pos);
+        byteStream[pos++] = this.requestedQos[i];
+      }
+
+      break;
+
+    case MESSAGE_TYPE.UNSUBSCRIBE:
+      // UNSUBSCRIBE has a list of topic strings
+      for (var i = 0; i < this.topics.length; i++) {
+        pos = writeString(this.topics[i], topicStrLength[i], byteStream, pos);
+      }
+
+      break;
+
+    default: // Do nothing.
+
+  }
+
+  return buffer;
+};
+
+export default WireMessage;
\ No newline at end of file

es/consts.js

+/* eslint-disable */
+export var MESSAGE_TYPE = {
+  CONNECT: 1,
+  CONNACK: 2,
+  PUBLISH: 3,
+  PUBACK: 4,
+  PUBREC: 5,
+  PUBREL: 6,
+  PUBCOMP: 7,
+  SUBSCRIBE: 8,
+  SUBACK: 9,
+  UNSUBSCRIBE: 10,
+  UNSUBACK: 11,
+  PINGREQ: 12,
+  PINGRESP: 13,
+  DISCONNECT: 14
+};
+/**
+ * Unique message type identifiers, with associated
+ * associated integer values.
+ * @private
+ */
+
+export var ERROR = {
+  OK: {
+    code: 0,
+    text: "AMQJSC0000I OK."
+  },
+  CONNECT_TIMEOUT: {
+    code: 1,
+    text: "AMQJSC0001E Connect timed out."
+  },
+  SUBSCRIBE_TIMEOUT: {
+    code: 2,
+    text: "AMQJS0002E Subscribe timed out."
+  },
+  UNSUBSCRIBE_TIMEOUT: {
+    code: 3,
+    text: "AMQJS0003E Unsubscribe timed out."
+  },
+  PING_TIMEOUT: {
+    code: 4,
+    text: "AMQJS0004E Ping timed out."
+  },
+  INTERNAL_ERROR: {
+    code: 5,
+    text: "AMQJS0005E Internal error. Error Message: {0}, Stack trace: {1}"
+  },
+  CONNACK_RETURNCODE: {
+    code: 6,
+    text: "AMQJS0006E Bad Connack return code:{0} {1}."
+  },
+  SOCKET_ERROR: {
+    code: 7,
+    text: "AMQJS0007E Socket error:{0}."
+  },
+  SOCKET_CLOSE: {
+    code: 8,
+    text: "AMQJS0008I Socket closed."
+  },
+  MALFORMED_UTF: {
+    code: 9,
+    text: "AMQJS0009E Malformed UTF data:{0} {1} {2}."
+  },
+  UNSUPPORTED: {
+    code: 10,
+    text: "AMQJS0010E {0} is not supported by this browser."
+  },
+  INVALID_STATE: {
+    code: 11,
+    text: "AMQJS0011E Invalid state {0}."
+  },
+  INVALID_TYPE: {
+    code: 12,
+    text: "AMQJS0012E Invalid type {0} for {1}."
+  },
+  INVALID_ARGUMENT: {
+    code: 13,
+    text: "AMQJS0013E Invalid argument {0} for {1}."
+  },
+  UNSUPPORTED_OPERATION: {
+    code: 14,
+    text: "AMQJS0014E Unsupported operation."
+  },
+  INVALID_STORED_DATA: {
+    code: 15,
+    text: "AMQJS0015E Invalid data in local storage key={0} value={1}."
+  },
+  INVALID_MQTT_MESSAGE_TYPE: {
+    code: 16,
+    text: "AMQJS0016E Invalid MQTT message type {0}."
+  },
+  MALFORMED_UNICODE: {
+    code: 17,
+    text: "AMQJS0017E Malformed Unicode string:{0} {1}."
+  },
+  BUFFER_FULL: {
+    code: 18,
+    text: "AMQJS0018E Message buffer is full, maximum buffer size: {0}."
+  }
+};
+/** CONNACK RC Meaning. */
+
+export var CONNACK_RC = {
+  0: "Connection Accepted",
+  1: "Connection Refused: unacceptable protocol version",
+  2: "Connection Refused: identifier rejected",
+  3: "Connection Refused: server unavailable",
+  4: "Connection Refused: bad user name or password",
+  5: "Connection Refused: not authorized"
+}; //MQTT protocol and version          6    M    Q    I    s    d    p    3
+
+export var MqttProtoIdentifierv3 = [0x00, 0x06, 0x4d, 0x51, 0x49, 0x73, 0x64, 0x70, 0x03]; //MQTT proto/version for 311         4    M    Q    T    T    4
+
+export var MqttProtoIdentifierv4 = [0x00, 0x04, 0x4d, 0x51, 0x54, 0x54, 0x04];
\ No newline at end of file

es/index.js

+import Client from './Client';
+import Message from './Message';
+/* eslint-disable */
+
+var MqttClient = {
+  Client: Client,
+  Message: Message
+};
+export default MqttClient;
\ No newline at end of file

es/utils.js

+import _typeof from "@babel/runtime/helpers/esm/typeof";
+import { ERROR, MESSAGE_TYPE } from './consts';
+import Message from './Message';
+import WireMessage from './WireMessage';
+/* eslint-disable */
+
+/**
+ * Validate an object's parameter names to ensure they
+ * match a list of expected variables name for this option
+ * type. Used to ensure option object passed into the API don't
+ * contain erroneous parameters.
+ * @param {Object} obj - User options object
+ * @param {Object} keys - valid keys and types that may exist in obj.
+ * @throws {Error} Invalid option parameter found.
+ * @private
+ */
+
+export var validate = function validate(obj, keys) {
+  for (var key in obj) {
+    if (obj.hasOwnProperty(key)) {
+      if (keys.hasOwnProperty(key)) {
+        if (_typeof(obj[key]) !== keys[key]) throw new Error(format(ERROR.INVALID_TYPE, [_typeof(obj[key]), key]));
+      } else {
+        var errorStr = 'Unknown property, ' + key + '. Valid properties are:';
+
+        for (var validKey in keys) {
+          if (keys.hasOwnProperty(validKey)) errorStr = errorStr + ' ' + validKey;
+        }
+
+        throw new Error(errorStr);
+      }
+    }
+  }
+};
+/**
+ * Format an error message text.
+ * @private
+ * @param {error} ERROR value above.
+ * @param {substitutions} [array] substituted into the text.
+ * @return the text with the substitutions made.
+ */
+
+export var format = function format(error, substitutions) {
+  var text = error.text;
+
+  if (substitutions) {
+    var field, start;
+
+    for (var i = 0; i < substitutions.length; i++) {
+      field = '{' + i + '}';
+      start = text.indexOf(field);
+
+      if (start > 0) {
+        var part1 = text.substring(0, start);
+        var part2 = text.substring(start + field.length);
+        text = part1 + substitutions[i] + part2;
+      }
+    }
+  }
+
+  return text;
+};
+export function decodeMessage(input, pos) {
+  var startingPos = pos;
+  var first = input[pos];
+  var type = first >> 4;
+  var messageInfo = first &= 0x0f;
+  pos += 1; // Decode the remaining length (MBI format)
+
+  var digit;
+  var remLength = 0;
+  var multiplier = 1;
+
+  do {
+    if (pos == input.length) {
+      return [null, startingPos];
+    }
+
+    digit = input[pos++];
+    remLength += (digit & 0x7f) * multiplier;
+    multiplier *= 128;
+  } while ((digit & 0x80) !== 0);
+
+  var endPos = pos + remLength;
+
+  if (endPos > input.length) {
+    return [null, startingPos];
+  }
+
+  var wireMessage = new WireMessage(type);
+
+  switch (type) {
+    case MESSAGE_TYPE.CONNACK:
+      var connectAcknowledgeFlags = input[pos++];
+      if (connectAcknowledgeFlags & 0x01) wireMessage.sessionPresent = true;
+      wireMessage.returnCode = input[pos++];
+      break;
+
+    case MESSAGE_TYPE.PUBLISH:
+      var qos = messageInfo >> 1 & 0x03;
+      var len = readUint16(input, pos);
+      pos += 2;
+      var topicName = parseUTF8(input, pos, len);
+      pos += len; // If QoS 1 or 2 there will be a messageIdentifier
+
+      if (qos > 0) {
+        wireMessage.messageIdentifier = readUint16(input, pos);
+        pos += 2;
+      }
+
+      var message = new Message(input.subarray(pos, endPos));
+      if ((messageInfo & 0x01) == 0x01) message.retained = true;
+      if ((messageInfo & 0x08) == 0x08) message.duplicate = true;
+      message.qos = qos;
+      message.destinationName = topicName;
+      wireMessage.payloadMessage = message;
+      break;
+
+    case MESSAGE_TYPE.PUBACK:
+    case MESSAGE_TYPE.PUBREC:
+    case MESSAGE_TYPE.PUBREL:
+    case MESSAGE_TYPE.PUBCOMP:
+    case MESSAGE_TYPE.UNSUBACK:
+      wireMessage.messageIdentifier = readUint16(input, pos);
+      break;
+
+    case MESSAGE_TYPE.SUBACK:
+      wireMessage.messageIdentifier = readUint16(input, pos);
+      pos += 2;
+      wireMessage.returnCode = input.subarray(pos, endPos);
+      break;
+
+    default:
+      break;
+  }
+
+  return [wireMessage, endPos];
+}
+export function writeUint16(input, buffer, offset) {
+  buffer[offset++] = input >> 8; //MSB
+
+  buffer[offset++] = input % 256; //LSB
+
+  return offset;
+}
+export function writeString(input, utf8Length, buffer, offset) {
+  offset = writeUint16(utf8Length, buffer, offset);
+  stringToUTF8(input, buffer, offset);
+  return offset + utf8Length;
+}
+export function readUint16(buffer, offset) {
+  return 256 * buffer[offset] + buffer[offset + 1];
+}
+/**
+ * Encodes an MQTT Multi-Byte Integer
+ * @private
+ */
+
+export function encodeMBI(number) {
+  var output = new Array(1);
+  var numBytes = 0;
+
+  do {
+    var digit = number % 128;
+    number = number >> 7;
+
+    if (number > 0) {
+      digit |= 0x80;
+    }
+
+    output[numBytes++] = digit;
+  } while (number > 0 && numBytes < 4);
+
+  return output;
+}
+/**
+ * Takes a String and calculates its length in bytes when encoded in UTF8.
+ * @private
+ */
+
+export function UTF8Length(input) {
+  var output = 0;
+
+  for (var i = 0; i < input.length; i++) {
+    var charCode = input.charCodeAt(i);
+
+    if (charCode > 0x7ff) {
+      // Surrogate pair means its a 4 byte character
+      if (0xd800 <= charCode && charCode <= 0xdbff) {
+        i++;
+        output++;
+      }
+
+      output += 3;
+    } else if (charCode > 0x7f) output += 2;else output++;
+  }
+
+  return output;
+}
+/**
+ * Takes a String and writes it into an array as UTF8 encoded bytes.
+ * @private
+ */
+
+export function stringToUTF8(input, output, start) {
+  var pos = start;
+
+  for (var i = 0; i < input.length; i++) {
+    var charCode = input.charCodeAt(i); // Check for a surrogate pair.
+
+    if (0xd800 <= charCode && charCode <= 0xdbff) {
+      var lowCharCode = input.charCodeAt(++i);
+
+      if (isNaN(lowCharCode)) {
+        throw new Error(format(ERROR.MALFORMED_UNICODE, [charCode, lowCharCode]));
+      }
+
+      charCode = (charCode - 0xd800 << 10) + (lowCharCode - 0xdc00) + 0x10000;
+    }
+
+    if (charCode <= 0x7f) {
+      output[pos++] = charCode;
+    } else if (charCode <= 0x7ff) {
+      output[pos++] = charCode >> 6 & 0x1f | 0xc0;
+      output[pos++] = charCode & 0x3f | 0x80;
+    } else if (charCode <= 0xffff) {
+      output[pos++] = charCode >> 12 & 0x0f | 0xe0;
+      output[pos++] = charCode >> 6 & 0x3f | 0x80;
+      output[pos++] = charCode & 0x3f | 0x80;
+    } else {
+      output[pos++] = charCode >> 18 & 0x07 | 0xf0;
+      output[pos++] = charCode >> 12 & 0x3f | 0x80;
+      output[pos++] = charCode >> 6 & 0x3f | 0x80;
+      output[pos++] = charCode & 0x3f | 0x80;
+    }
+  }
+
+  return output;
+}
+export function parseUTF8(input, offset, length) {
+  var output = '';
+  var utf16;
+  var pos = offset;
+
+  while (pos < offset + length) {
+    var byte1 = input[pos++];
+    if (byte1 < 128) utf16 = byte1;else {
+      var byte2 = input[pos++] - 128;
+      if (byte2 < 0) throw new Error(format(ERROR.MALFORMED_UTF, [byte1.toString(16), byte2.toString(16), '']));
+      if (byte1 < 0xe0) // 2 byte character
+        utf16 = 64 * (byte1 - 0xc0) + byte2;else {
+        var byte3 = input[pos++] - 128;
+        if (byte3 < 0) throw new Error(format(ERROR.MALFORMED_UTF, [byte1.toString(16), byte2.toString(16), byte3.toString(16)]));
+        if (byte1 < 0xf0) // 3 byte character
+          utf16 = 4096 * (byte1 - 0xe0) + 64 * byte2 + byte3;else {
+          var byte4 = input[pos++] - 128;
+          if (byte4 < 0) throw new Error(format(ERROR.MALFORMED_UTF, [byte1.toString(16), byte2.toString(16), byte3.toString(16), byte4.toString(16)]));
+          if (byte1 < 0xf8) // 4 byte character
+            utf16 = 262144 * (byte1 - 0xf0) + 4096 * byte2 + 64 * byte3 + byte4; // longer encodings are not supported
+          else throw new Error(format(ERROR.MALFORMED_UTF, [byte1.toString(16), byte2.toString(16), byte3.toString(16), byte4.toString(16)]));
+        }
+      }
+    }
+
+    if (utf16 > 0xffff) {
+      // 4 byte character - express as a surrogate pair
+      utf16 -= 0x10000;
+      output += String.fromCharCode(0xd800 + (utf16 >> 10)); // lead character
+
+      utf16 = 0xdc00 + (utf16 & 0x3ff); // trail character
+    }
+
+    output += String.fromCharCode(utf16);
+  }
+
+  return output;
+}
\ No newline at end of file

lib/Message.js

+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.default = void 0;
+
+var _consts = require("./consts");
+
+var _utils = require("./utils");
+
+/* eslint-disable */
+var Message = function Message(newPayload) {
+  var payload;
+
+  if (typeof newPayload === 'string' || newPayload instanceof ArrayBuffer || ArrayBuffer.isView(newPayload) && !(newPayload instanceof DataView)) {
+    payload = newPayload;
+  } else {
+    throw (0, _utils.format)(_consts.ERROR.INVALID_ARGUMENT, [newPayload, 'newPayload']);
+  }
+
+  var destinationName;
+  var qos = 0;
+  var retained = false;
+  var duplicate = false;
+  Object.defineProperties(this, {
+    payloadString: {
+      enumerable: true,
+      get: function get() {
+        if (typeof payload === 'string') return payload;else return (0, _utils.parseUTF8)(payload, 0, payload.length);
+      }
+    },
+    payloadBytes: {
+      enumerable: true,
+      get: function get() {
+        if (typeof payload === 'string') {
+          var buffer = new ArrayBuffer((0, _utils.UTF8Length)(payload));
+          var byteStream = new Uint8Array(buffer);
+          (0, _utils.stringToUTF8)(payload, byteStream, 0);
+          return byteStream;
+        } else {
+          return payload;
+        }
+      }
+    },
+    destinationName: {
+      enumerable: true,
+      get: function get() {
+        return destinationName;
+      },
+      set: function set(newDestinationName) {
+        if (typeof newDestinationName === 'string') destinationName = newDestinationName;else throw new Error((0, _utils.format)(_consts.ERROR.INVALID_ARGUMENT, [newDestinationName, 'newDestinationName']));
+      }
+    },
+    qos: {
+      enumerable: true,
+      get: function get() {
+        return qos;
+      },
+      set: function set(newQos) {
+        if (newQos === 0 || newQos === 1 || newQos === 2) qos = newQos;else throw new Error('Invalid argument:' + newQos);
+      }
+    },
+    retained: {
+      enumerable: true,
+      get: function get() {
+        return retained;
+      },
+      set: function set(newRetained) {
+        if (typeof newRetained === 'boolean') retained = newRetained;else throw new Error((0, _utils.format)(_consts.ERROR.INVALID_ARGUMENT, [newRetained, 'newRetained']));
+      }
+    },
+    topic: {
+      enumerable: true,
+      get: function get() {
+        return destinationName;
+      },
+      set: function set(newTopic) {
+        destinationName = newTopic;
+      }
+    },
+    duplicate: {
+      enumerable: true,
+      get: function get() {
+        return duplicate;
+      },
+      set: function set(newDuplicate) {
+        duplicate = newDuplicate;
+      }
+    }
+  });
+};
+
+var _default = Message;
+exports.default = _default;
\ No newline at end of file

lib/Pinger.js

+"use strict";
+
+var _interopRequireDefault = require("@babel/runtime/helpers/interopRequireDefault");
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.default = void 0;
+
+var _consts = require("./consts");
+
+var _utils = require("./utils");
+
+var _WireMessage = _interopRequireDefault(require("./WireMessage"));
+
+/* eslint-disable */
+var Pinger = function Pinger(client, keepAliveInterval) {
+  this._client = client;
+  this._keepAliveInterval = keepAliveInterval * 1000;
+  this.isReset = false;
+  var pingReq = new _WireMessage.default(_consts.MESSAGE_TYPE.PINGREQ).encode();
+
+  var doTimeout = function doTimeout(pinger) {
+    return function () {
+      return doPing.apply(pinger);
+    };
+  };
+  /** @ignore */
+
+
+  var doPing = function doPing() {
+    if (!this.isReset) {
+      this._client._trace("Pinger.doPing", "Timed out");
+
+      this._client._disconnected(_consts.ERROR.PING_TIMEOUT.code, (0, _utils.format)(_consts.ERROR.PING_TIMEOUT));
+    } else {
+      this.isReset = false;
+
+      this._client._trace("Pinger.doPing", "send PINGREQ");
+
+      this._client.socket.send(pingReq);
+
+      this.timeout = setTimeout(doTimeout(this), this._keepAliveInterval);
+    }
+  };
+
+  this.reset = function () {
+    this.isReset = true;
+    clearTimeout(this.timeout);
+    if (this._keepAliveInterval > 0) this.timeout = setTimeout(doTimeout(this), this._keepAliveInterval);
+  };
+
+  this.cancel = function () {
+    clearTimeout(this.timeout);
+  };
+};
+
+var _default = Pinger;
+exports.default = _default;
\ No newline at end of file

lib/WireMessage.js

+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.default = void 0;
+
+var _consts = require("./consts");
+
+var _utils = require("./utils");
+
+/* eslint-disable */
+// interface WireMessageOptions {
+//     messageIdentifier?: number
+//     mqttVersion?: 3 | 4
+//     clientId?: string
+//     willMessage?: MqttMessage
+//     userName?: string
+//     password?: string
+//     topics?: string[]
+//     requestedQos?: (0 | 1 | 2)[]
+//     payloadMessage?: MqttMessage
+//     cleanSession?: boolean
+//     keepAliveInterval?: number
+//     [key: string]: any
+//   }
+var WireMessage = function WireMessage(type, options) {
+  this.type = type;
+
+  for (var name in options) {
+    if (options.hasOwnProperty(name)) {
+      this[name] = options[name];
+    }
+  }
+};
+
+WireMessage.prototype.encode = function () {
+  // Compute the first byte of the fixed header
+  var first = (this.type & 0x0f) << 4;
+  /*
+  * Now calculate the length of the variable header + payload by adding up the lengths
+  * of all the component parts
+  */
+
+  var remLength = 0;
+  var topicStrLength = [];
+  var destinationNameLength = 0;
+  var willMessagePayloadBytes; // if the message contains a messageIdentifier then we need two bytes for that
+
+  if (this.messageIdentifier !== undefined) remLength += 2;
+
+  switch (this.type) {
+    // If this a Connect then we need to include 12 bytes for its header
+    case _consts.MESSAGE_TYPE.CONNECT:
+      switch (this.mqttVersion) {
+        case 3:
+          remLength += _consts.MqttProtoIdentifierv3.length + 3;
+          break;
+
+        case 4:
+          remLength += _consts.MqttProtoIdentifierv4.length + 3;
+          break;
+      }
+
+      remLength += (0, _utils.UTF8Length)(this.clientId) + 2;
+
+      if (this.willMessage !== undefined) {
+        remLength += (0, _utils.UTF8Length)(this.willMessage.destinationName) + 2; // Will message is always a string, sent as UTF-8 characters with a preceding length.
+
+        willMessagePayloadBytes = this.willMessage.payloadBytes;
+        if (!(willMessagePayloadBytes instanceof Uint8Array)) willMessagePayloadBytes = new Uint8Array(payloadBytes);
+        remLength += willMessagePayloadBytes.byteLength + 2;
+      }
+
+      if (this.userName !== undefined) remLength += (0, _utils.UTF8Length)(this.userName) + 2;
+      if (this.password !== undefined) remLength += (0, _utils.UTF8Length)(this.password) + 2;
+      break;
+    // Subscribe, Unsubscribe can both contain topic strings
+
+    case _consts.MESSAGE_TYPE.SUBSCRIBE:
+      first |= 0x02; // Qos = 1;
+
+      for (var i = 0; i < this.topics.length; i++) {
+        topicStrLength[i] = (0, _utils.UTF8Length)(this.topics[i]);
+        remLength += topicStrLength[i] + 2;
+      }
+
+      remLength += this.requestedQos.length; // 1 byte for each topic's Qos
+      // QoS on Subscribe only
+
+      break;
+
+    case _consts.MESSAGE_TYPE.UNSUBSCRIBE:
+      first |= 0x02; // Qos = 1;
+
+      for (var i = 0; i < this.topics.length; i++) {
+        topicStrLength[i] = (0, _utils.UTF8Length)(this.topics[i]);
+        remLength += topicStrLength[i] + 2;
+      }
+
+      break;
+
+    case _consts.MESSAGE_TYPE.PUBREL:
+      first |= 0x02; // Qos = 1;
+
+      break;
+
+    case _consts.MESSAGE_TYPE.PUBLISH:
+      if (this.payloadMessage.duplicate) first |= 0x08;
+      first = first |= this.payloadMessage.qos << 1;
+      if (this.payloadMessage.retained) first |= 0x01;
+      destinationNameLength = (0, _utils.UTF8Length)(this.payloadMessage.destinationName);
+      remLength += destinationNameLength + 2;
+      var payloadBytes = this.payloadMessage.payloadBytes;
+      remLength += payloadBytes.byteLength;
+      if (payloadBytes instanceof ArrayBuffer) payloadBytes = new Uint8Array(payloadBytes);else if (!(payloadBytes instanceof Uint8Array)) payloadBytes = new Uint8Array(payloadBytes.buffer);
+      break;
+
+    case _consts.MESSAGE_TYPE.DISCONNECT:
+      break;
+
+    default:
+      break;
+  } // Now we can allocate a buffer for the message
+
+
+  var mbi = (0, _utils.encodeMBI)(remLength); // Convert the length to MQTT MBI format
+
+  var pos = mbi.length + 1; // Offset of start of variable header
+
+  var buffer = new ArrayBuffer(remLength + pos);
+  var byteStream = new Uint8Array(buffer); // view it as a sequence of bytes
+  //Write the fixed header into the buffer
+
+  byteStream[0] = first;
+  byteStream.set(mbi, 1); // If this is a PUBLISH then the variable header starts with a topic
+
+  if (this.type == _consts.MESSAGE_TYPE.PUBLISH) pos = (0, _utils.writeString)(this.payloadMessage.destinationName, destinationNameLength, byteStream, pos); // If this is a CONNECT then the variable header contains the protocol name/version, flags and keepalive time
+  else if (this.type == _consts.MESSAGE_TYPE.CONNECT) {
+    switch (this.mqttVersion) {
+      case 3:
+        byteStream.set(_consts.MqttProtoIdentifierv3, pos);
+        pos += _consts.MqttProtoIdentifierv3.length;
+        break;
+
+      case 4:
+        byteStream.set(_consts.MqttProtoIdentifierv4, pos);
+        pos += _consts.MqttProtoIdentifierv4.length;
+        break;
+    }
+
+    var connectFlags = 0;
+    if (this.cleanSession) connectFlags = 0x02;
+
+    if (this.willMessage !== undefined) {
+      connectFlags |= 0x04;
+      connectFlags |= this.willMessage.qos << 3;
+
+      if (this.willMessage.retained) {
+        connectFlags |= 0x20;
+      }
+    }
+
+    if (this.userName !== undefined) connectFlags |= 0x80;
+    if (this.password !== undefined) connectFlags |= 0x40;
+    byteStream[pos++] = connectFlags;
+    pos = (0, _utils.writeUint16)(this.keepAliveInterval, byteStream, pos);
+  } // Output the messageIdentifier - if there is one
+
+  if (this.messageIdentifier !== undefined) pos = (0, _utils.writeUint16)(this.messageIdentifier, byteStream, pos);
+
+  switch (this.type) {
+    case _consts.MESSAGE_TYPE.CONNECT:
+      pos = (0, _utils.writeString)(this.clientId, (0, _utils.UTF8Length)(this.clientId), byteStream, pos);
+
+      if (this.willMessage !== undefined) {
+        pos = (0, _utils.writeString)(this.willMessage.destinationName, (0, _utils.UTF8Length)(this.willMessage.destinationName), byteStream, pos);
+        pos = (0, _utils.writeUint16)(willMessagePayloadBytes.byteLength, byteStream, pos);
+        byteStream.set(willMessagePayloadBytes, pos);
+        pos += willMessagePayloadBytes.byteLength;
+      }
+
+      if (this.userName !== undefined) pos = (0, _utils.writeString)(this.userName, (0, _utils.UTF8Length)(this.userName), byteStream, pos);
+      if (this.password !== undefined) pos = (0, _utils.writeString)(this.password, (0, _utils.UTF8Length)(this.password), byteStream, pos);
+      break;
+
+    case _consts.MESSAGE_TYPE.PUBLISH:
+      // PUBLISH has a text or binary payload, if text do not add a 2 byte length field, just the UTF characters.
+      byteStream.set(payloadBytes, pos);
+      break;
+    //    	    case MESSAGE_TYPE.PUBREC:
+    //    	    case MESSAGE_TYPE.PUBREL:
+    //    	    case MESSAGE_TYPE.PUBCOMP:
+    //    	    	break;
+
+    case _consts.MESSAGE_TYPE.SUBSCRIBE:
+      // SUBSCRIBE has a list of topic strings and request QoS
+      for (var i = 0; i < this.topics.length; i++) {
+        pos = (0, _utils.writeString)(this.topics[i], topicStrLength[i], byteStream, pos);
+        byteStream[pos++] = this.requestedQos[i];
+      }
+
+      break;
+
+    case _consts.MESSAGE_TYPE.UNSUBSCRIBE:
+      // UNSUBSCRIBE has a list of topic strings
+      for (var i = 0; i < this.topics.length; i++) {
+        pos = (0, _utils.writeString)(this.topics[i], topicStrLength[i], byteStream, pos);
+      }
+
+      break;
+
+    default: // Do nothing.
+
+  }
+
+  return buffer;
+};
+
+var _default = WireMessage;
+exports.default = _default;
\ No newline at end of file

lib/consts.js

+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.MqttProtoIdentifierv4 = exports.MqttProtoIdentifierv3 = exports.MESSAGE_TYPE = exports.ERROR = exports.CONNACK_RC = void 0;
+
+/* eslint-disable */
+var MESSAGE_TYPE = {
+  CONNECT: 1,
+  CONNACK: 2,
+  PUBLISH: 3,
+  PUBACK: 4,
+  PUBREC: 5,
+  PUBREL: 6,
+  PUBCOMP: 7,
+  SUBSCRIBE: 8,
+  SUBACK: 9,
+  UNSUBSCRIBE: 10,
+  UNSUBACK: 11,
+  PINGREQ: 12,
+  PINGRESP: 13,
+  DISCONNECT: 14
+};
+/**
+ * Unique message type identifiers, with associated
+ * associated integer values.
+ * @private
+ */
+
+exports.MESSAGE_TYPE = MESSAGE_TYPE;
+var ERROR = {
+  OK: {
+    code: 0,
+    text: "AMQJSC0000I OK."
+  },
+  CONNECT_TIMEOUT: {
+    code: 1,
+    text: "AMQJSC0001E Connect timed out."
+  },
+  SUBSCRIBE_TIMEOUT: {
+    code: 2,
+    text: "AMQJS0002E Subscribe timed out."
+  },
+  UNSUBSCRIBE_TIMEOUT: {
+    code: 3,
+    text: "AMQJS0003E Unsubscribe timed out."
+  },
+  PING_TIMEOUT: {
+    code: 4,
+    text: "AMQJS0004E Ping timed out."
+  },
+  INTERNAL_ERROR: {
+    code: 5,
+    text: "AMQJS0005E Internal error. Error Message: {0}, Stack trace: {1}"
+  },
+  CONNACK_RETURNCODE: {
+    code: 6,
+    text: "AMQJS0006E Bad Connack return code:{0} {1}."
+  },
+  SOCKET_ERROR: {
+    code: 7,
+    text: "AMQJS0007E Socket error:{0}."
+  },
+  SOCKET_CLOSE: {
+    code: 8,
+    text: "AMQJS0008I Socket closed."
+  },
+  MALFORMED_UTF: {
+    code: 9,
+    text: "AMQJS0009E Malformed UTF data:{0} {1} {2}."
+  },
+  UNSUPPORTED: {
+    code: 10,
+    text: "AMQJS0010E {0} is not supported by this browser."
+  },
+  INVALID_STATE: {
+    code: 11,
+    text: "AMQJS0011E Invalid state {0}."
+  },
+  INVALID_TYPE: {
+    code: 12,
+    text: "AMQJS0012E Invalid type {0} for {1}."
+  },
+  INVALID_ARGUMENT: {
+    code: 13,
+    text: "AMQJS0013E Invalid argument {0} for {1}."
+  },
+  UNSUPPORTED_OPERATION: {
+    code: 14,
+    text: "AMQJS0014E Unsupported operation."
+  },
+  INVALID_STORED_DATA: {
+    code: 15,
+    text: "AMQJS0015E Invalid data in local storage key={0} value={1}."
+  },
+  INVALID_MQTT_MESSAGE_TYPE: {
+    code: 16,
+    text: "AMQJS0016E Invalid MQTT message type {0}."
+  },
+  MALFORMED_UNICODE: {
+    code: 17,
+    text: "AMQJS0017E Malformed Unicode string:{0} {1}."
+  },
+  BUFFER_FULL: {
+    code: 18,
+    text: "AMQJS0018E Message buffer is full, maximum buffer size: {0}."
+  }
+};
+/** CONNACK RC Meaning. */
+
+exports.ERROR = ERROR;
+var CONNACK_RC = {
+  0: "Connection Accepted",
+  1: "Connection Refused: unacceptable protocol version",
+  2: "Connection Refused: identifier rejected",
+  3: "Connection Refused: server unavailable",
+  4: "Connection Refused: bad user name or password",
+  5: "Connection Refused: not authorized"
+}; //MQTT protocol and version          6    M    Q    I    s    d    p    3
+
+exports.CONNACK_RC = CONNACK_RC;
+var MqttProtoIdentifierv3 = [0x00, 0x06, 0x4d, 0x51, 0x49, 0x73, 0x64, 0x70, 0x03]; //MQTT proto/version for 311         4    M    Q    T    T    4
+
+exports.MqttProtoIdentifierv3 = MqttProtoIdentifierv3;
+var MqttProtoIdentifierv4 = [0x00, 0x04, 0x4d, 0x51, 0x54, 0x54, 0x04];
+exports.MqttProtoIdentifierv4 = MqttProtoIdentifierv4;
\ No newline at end of file

lib/index.js

+"use strict";
+
+var _interopRequireDefault = require("@babel/runtime/helpers/interopRequireDefault");
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.default = void 0;
+
+var _Client = _interopRequireDefault(require("./Client"));
+
+var _Message = _interopRequireDefault(require("./Message"));
+
+/* eslint-disable */
+var MqttClient = {
+  Client: _Client.default,
+  Message: _Message.default
+};
+var _default = MqttClient;
+exports.default = _default;
\ No newline at end of file

lib/utils.js

+"use strict";
+
+var _interopRequireDefault = require("@babel/runtime/helpers/interopRequireDefault");
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.UTF8Length = UTF8Length;
+exports.decodeMessage = decodeMessage;
+exports.encodeMBI = encodeMBI;
+exports.format = void 0;
+exports.parseUTF8 = parseUTF8;
+exports.readUint16 = readUint16;
+exports.stringToUTF8 = stringToUTF8;
+exports.validate = void 0;
+exports.writeString = writeString;
+exports.writeUint16 = writeUint16;
+
+var _typeof2 = _interopRequireDefault(require("@babel/runtime/helpers/typeof"));
+
+var _consts = require("./consts");
+
+var _Message = _interopRequireDefault(require("./Message"));
+
+var _WireMessage = _interopRequireDefault(require("./WireMessage"));
+
+/* eslint-disable */
+
+/**
+ * Validate an object's parameter names to ensure they
+ * match a list of expected variables name for this option
+ * type. Used to ensure option object passed into the API don't
+ * contain erroneous parameters.
+ * @param {Object} obj - User options object
+ * @param {Object} keys - valid keys and types that may exist in obj.
+ * @throws {Error} Invalid option parameter found.
+ * @private
+ */
+var validate = function validate(obj, keys) {
+  for (var key in obj) {
+    if (obj.hasOwnProperty(key)) {
+      if (keys.hasOwnProperty(key)) {
+        if ((0, _typeof2.default)(obj[key]) !== keys[key]) throw new Error(format(_consts.ERROR.INVALID_TYPE, [(0, _typeof2.default)(obj[key]), key]));
+      } else {
+        var errorStr = 'Unknown property, ' + key + '. Valid properties are:';
+
+        for (var validKey in keys) {
+          if (keys.hasOwnProperty(validKey)) errorStr = errorStr + ' ' + validKey;
+        }
+
+        throw new Error(errorStr);
+      }
+    }
+  }
+};
+/**
+ * Format an error message text.
+ * @private
+ * @param {error} ERROR value above.
+ * @param {substitutions} [array] substituted into the text.
+ * @return the text with the substitutions made.
+ */
+
+
+exports.validate = validate;
+
+var format = function format(error, substitutions) {
+  var text = error.text;
+
+  if (substitutions) {
+    var field, start;
+
+    for (var i = 0; i < substitutions.length; i++) {
+      field = '{' + i + '}';
+      start = text.indexOf(field);
+
+      if (start > 0) {
+        var part1 = text.substring(0, start);
+        var part2 = text.substring(start + field.length);
+        text = part1 + substitutions[i] + part2;
+      }
+    }
+  }
+
+  return text;
+};
+
+exports.format = format;
+
+function decodeMessage(input, pos) {
+  var startingPos = pos;
+  var first = input[pos];
+  var type = first >> 4;
+  var messageInfo = first &= 0x0f;
+  pos += 1; // Decode the remaining length (MBI format)
+
+  var digit;
+  var remLength = 0;
+  var multiplier = 1;
+
+  do {
+    if (pos == input.length) {
+      return [null, startingPos];
+    }
+
+    digit = input[pos++];
+    remLength += (digit & 0x7f) * multiplier;
+    multiplier *= 128;
+  } while ((digit & 0x80) !== 0);
+
+  var endPos = pos + remLength;
+
+  if (endPos > input.length) {
+    return [null, startingPos];
+  }
+
+  var wireMessage = new _WireMessage.default(type);
+
+  switch (type) {
+    case _consts.MESSAGE_TYPE.CONNACK:
+      var connectAcknowledgeFlags = input[pos++];
+      if (connectAcknowledgeFlags & 0x01) wireMessage.sessionPresent = true;
+      wireMessage.returnCode = input[pos++];
+      break;
+
+    case _consts.MESSAGE_TYPE.PUBLISH:
+      var qos = messageInfo >> 1 & 0x03;
+      var len = readUint16(input, pos);
+      pos += 2;
+      var topicName = parseUTF8(input, pos, len);
+      pos += len; // If QoS 1 or 2 there will be a messageIdentifier
+
+      if (qos > 0) {
+        wireMessage.messageIdentifier = readUint16(input, pos);
+        pos += 2;
+      }
+
+      var message = new _Message.default(input.subarray(pos, endPos));
+      if ((messageInfo & 0x01) == 0x01) message.retained = true;
+      if ((messageInfo & 0x08) == 0x08) message.duplicate = true;
+      message.qos = qos;
+      message.destinationName = topicName;
+      wireMessage.payloadMessage = message;
+      break;
+
+    case _consts.MESSAGE_TYPE.PUBACK:
+    case _consts.MESSAGE_TYPE.PUBREC:
+    case _consts.MESSAGE_TYPE.PUBREL:
+    case _consts.MESSAGE_TYPE.PUBCOMP:
+    case _consts.MESSAGE_TYPE.UNSUBACK:
+      wireMessage.messageIdentifier = readUint16(input, pos);
+      break;
+
+    case _consts.MESSAGE_TYPE.SUBACK:
+      wireMessage.messageIdentifier = readUint16(input, pos);
+      pos += 2;
+      wireMessage.returnCode = input.subarray(pos, endPos);
+      break;
+
+    default:
+      break;
+  }
+
+  return [wireMessage, endPos];
+}
+
+function writeUint16(input, buffer, offset) {
+  buffer[offset++] = input >> 8; //MSB
+
+  buffer[offset++] = input % 256; //LSB
+
+  return offset;
+}
+
+function writeString(input, utf8Length, buffer, offset) {
+  offset = writeUint16(utf8Length, buffer, offset);
+  stringToUTF8(input, buffer, offset);
+  return offset + utf8Length;
+}
+
+function readUint16(buffer, offset) {
+  return 256 * buffer[offset] + buffer[offset + 1];
+}
+/**
+ * Encodes an MQTT Multi-Byte Integer
+ * @private
+ */
+
+
+function encodeMBI(number) {
+  var output = new Array(1);
+  var numBytes = 0;
+
+  do {
+    var digit = number % 128;
+    number = number >> 7;
+
+    if (number > 0) {
+      digit |= 0x80;
+    }
+
+    output[numBytes++] = digit;
+  } while (number > 0 && numBytes < 4);
+
+  return output;
+}
+/**
+ * Takes a String and calculates its length in bytes when encoded in UTF8.
+ * @private
+ */
+
+
+function UTF8Length(input) {
+  var output = 0;
+
+  for (var i = 0; i < input.length; i++) {
+    var charCode = input.charCodeAt(i);
+
+    if (charCode > 0x7ff) {
+      // Surrogate pair means its a 4 byte character
+      if (0xd800 <= charCode && charCode <= 0xdbff) {
+        i++;
+        output++;
+      }
+
+      output += 3;
+    } else if (charCode > 0x7f) output += 2;else output++;
+  }
+
+  return output;
+}
+/**
+ * Takes a String and writes it into an array as UTF8 encoded bytes.
+ * @private
+ */
+
+
+function stringToUTF8(input, output, start) {
+  var pos = start;
+
+  for (var i = 0; i < input.length; i++) {
+    var charCode = input.charCodeAt(i); // Check for a surrogate pair.
+
+    if (0xd800 <= charCode && charCode <= 0xdbff) {
+      var lowCharCode = input.charCodeAt(++i);
+
+      if (isNaN(lowCharCode)) {
+        throw new Error(format(_consts.ERROR.MALFORMED_UNICODE, [charCode, lowCharCode]));
+      }
+
+      charCode = (charCode - 0xd800 << 10) + (lowCharCode - 0xdc00) + 0x10000;
+    }
+
+    if (charCode <= 0x7f) {
+      output[pos++] = charCode;
+    } else if (charCode <= 0x7ff) {
+      output[pos++] = charCode >> 6 & 0x1f | 0xc0;
+      output[pos++] = charCode & 0x3f | 0x80;
+    } else if (charCode <= 0xffff) {
+      output[pos++] = charCode >> 12 & 0x0f | 0xe0;
+      output[pos++] = charCode >> 6 & 0x3f | 0x80;
+      output[pos++] = charCode & 0x3f | 0x80;
+    } else {
+      output[pos++] = charCode >> 18 & 0x07 | 0xf0;
+      output[pos++] = charCode >> 12 & 0x3f | 0x80;
+      output[pos++] = charCode >> 6 & 0x3f | 0x80;
+      output[pos++] = charCode & 0x3f | 0x80;
+    }
+  }
+
+  return output;
+}
+
+function parseUTF8(input, offset, length) {
+  var output = '';
+  var utf16;
+  var pos = offset;
+
+  while (pos < offset + length) {
+    var byte1 = input[pos++];
+    if (byte1 < 128) utf16 = byte1;else {
+      var byte2 = input[pos++] - 128;
+      if (byte2 < 0) throw new Error(format(_consts.ERROR.MALFORMED_UTF, [byte1.toString(16), byte2.toString(16), '']));
+      if (byte1 < 0xe0) // 2 byte character
+        utf16 = 64 * (byte1 - 0xc0) + byte2;else {
+        var byte3 = input[pos++] - 128;
+        if (byte3 < 0) throw new Error(format(_consts.ERROR.MALFORMED_UTF, [byte1.toString(16), byte2.toString(16), byte3.toString(16)]));
+        if (byte1 < 0xf0) // 3 byte character
+          utf16 = 4096 * (byte1 - 0xe0) + 64 * byte2 + byte3;else {
+          var byte4 = input[pos++] - 128;
+          if (byte4 < 0) throw new Error(format(_consts.ERROR.MALFORMED_UTF, [byte1.toString(16), byte2.toString(16), byte3.toString(16), byte4.toString(16)]));
+          if (byte1 < 0xf8) // 4 byte character
+            utf16 = 262144 * (byte1 - 0xf0) + 4096 * byte2 + 64 * byte3 + byte4; // longer encodings are not supported
+          else throw new Error(format(_consts.ERROR.MALFORMED_UTF, [byte1.toString(16), byte2.toString(16), byte3.toString(16), byte4.toString(16)]));
+        }
+      }
+    }
+
+    if (utf16 > 0xffff) {
+      // 4 byte character - express as a surrogate pair
+      utf16 -= 0x10000;
+      output += String.fromCharCode(0xd800 + (utf16 >> 10)); // lead character
+
+      utf16 = 0xdc00 + (utf16 & 0x3ff); // trail character
+    }
+
+    output += String.fromCharCode(utf16);
+  }
+
+  return output;
+}
\ No newline at end of file