message: increased readability of hmac comparison input conditions
diff: @@ -37,7 +37,7 @@ class HmacValidator {
  if (notificationRequestItem.additionalData?.[ApiConstants.HMAC_SIGNATURE]) {
  const expectedSign = this.calculateHmac(notificationRequestItem, key);
  const merchantSign = notificationRequestItem.additionalData?.[ApiConstants.HMAC_SIGNATURE];
  - if(typeof merchantSign !== "undefined" && expectedSign.length === merchantSign.length) {
  + if(merchantSign && expectedSign.length === merchantSign.length) {
  return timingSafeEqual(
  Buffer.from(expectedSign, "base64"),
  Buffer.from(merchantSign, "base64")
  