How to use the iconv-lite.encode function in iconv-lite

function getEncryptedVars (data) {
  const utf16Data = iconv.encode(data, 'utf16')
  const keyBuf = crypto.createHash('sha256').update('abcdefghijk').digest()
  const ivBuf = Buffer.from('MTCSTA0000000009')
  const cipher = crypto.createCipheriv('aes-256-cbc', keyBuf, ivBuf)
  const buf1 = cipher.update(utf16Data)
  const buf2 = cipher.final()
  const encBuf = Buffer.concat([buf1, buf2])

  // We need to encrypt the keyBuf and ivBuf with the public key of the recipient
  const encKeyBuf = crypto.publicEncrypt(recipientFakePublicKey, keyBuf)
  const encIvBuf = crypto.publicEncrypt(recipientFakePublicKey, ivBuf)

  // Create a signature: a signed hash of the encrypted data using the senders private keyBuf
  const sign = crypto.createSign('RSA-SHA1')
  sign.write(encBuf)
  sign.end()
  const signatureB64 = sign.sign(senderFakePrivateKey, 'base64')

function toBuffer(buf, charset) {
  if (buf == null || Buffer.isBuffer(buf)) {
    return buf;
  }
  buf += '';
  if (charset && typeof charset === 'string' && !UTF8_RE.test(charset)) {
    try {
      charset = charset.toLowerCase();
      if (charset === 'base64') {
        return Buffer.from(buf, 'base64');
      }
      return iconv.encode(buf, charset);
    } catch (e) {}
  }
  return Buffer.from(buf);
}

export function encode(string, encoding = 'utf8') {
  if (encoding === 'utf8') return Buffer.from(string, 'utf8')

  if (!iconv.encodingExists(encoding))
    throw new Error(`Encoding does not exist: "${encoding}"`)

  return iconv.encode(string, encoding)
}

export default function adjustEncoding(config) {
	const input = fs.readFileSync(config.input);
	const inputFileEncoding = getEncoding(input);
	const output = fs.readFileSync(config.output.js);
	const outputFileEncoding = getEncoding(output);

	const sourceContent = iconv.decode(output, outputFileEncoding);
	const content = iconv.encode(sourceContent, inputFileEncoding);

	fs.writeFileSync(config.output.js, content);
}

function encode(text, useCesu8) {
  return (useCesu8) ?
    iconv.encode(text, 'cesu8') :
    new Buffer(text, 'utf-8');
}

this.getDoorSysBuffer = function() {
		var up			= self.client.user.properties;
		var now			= moment();
		var secLevel	= self.client.user.getLegacySecurityLevel().toString();

		//	:TODO: fix time remaining
		//	:TODO: fix default protocol -- user prop: transfer_protocol

		return iconv.encode( [
			'COM1:',											//	"Comm Port - COM0: = LOCAL MODE"
			'57600',											//	"Baud Rate - 300 to 38400" (Note: set as 57600 instead!)
			'8',												//	"Parity - 7 or 8"
			self.client.node.toString(),						//	"Node Number - 1 to 99"
			'57600',											//	"DTE Rate. Actual BPS rate to use. (kg)"
			'Y',												//	"Screen Display - Y=On  N=Off             (Default to Y)"
			'Y',												//	"Printer Toggle - Y=On  N=Off             (Default to Y)"
			'Y',												//	"Page Bell      - Y=On  N=Off             (Default to Y)"
			'Y',												//	"Caller Alarm   - Y=On  N=Off             (Default to Y)"
			up.real_name || self.client.user.username,			//	"User Full Name"
			up.location || 'Anywhere',							//	"Calling From"
			'123-456-7890',										//	"Home Phone"
			'123-456-7890',										//	"Work/Data Phone"
			'NOPE',												//	"Password" (Note: this is never given out or even stored plaintext)
			secLevel,											//	"Security Level"
			up.login_count.toString(),							//	"Total Times On"

function convertIconvLite(str, to, from) {
    if (to === 'UTF-8') {
        return iconvLite.decode(str, from);
    } else if (from === 'UTF-8') {
        return iconvLite.encode(str, to);
    } else {
        return iconvLite.encode(iconvLite.decode(str, from), to);
    }
}

Client.prototype.methodCall = function methodCall(method, params, callback) {
  var buff = Iconv.encode(Serializer.serializeMethodCall(method, params), 'ISO-8859-1')
    , transport = this.isSecure ? https : http
    , options   = this.options
    
  options.headers['Content-Length'] = buff.length
  options.headers['Content-Type'] = 'text/xml; charset=iso-8859-1'

  this.headersProcessors.composeRequest(options.headers)
  var request = transport.request(options, function(response) {
    if (response.statusCode == 404) {
      callback(new Error('Not Found'));
    }
    else {
      this.headersProcessors.parseResponse(response.headers)
      var deserializer = new Deserializer(options.responseEncoding)
      deserializer.deserializeMethodResponse(response, callback)
    }

function writeParam(out, val, encoding) {
  let param = Buffer.isEncoding(encoding)
    ? Buffer.from(val, encoding)
    : Iconv.encode(val, encoding);
  out.writeLengthCoded(param.length);
  out.writeBuffer(param, 0, param.length);
}