How to use the sodium-native.crypto_secretbox_easy function in sodium-native

if (!session || !session.changed) {
        // nothing to do
        next()
        return
      } else if (session.deleted) {
        const tmpCookieOptions = Object.assign({}, cookieOptions, { expires: new Date(0), maxAge: 0 })
        reply.setCookie(cookieName, '', tmpCookieOptions)
        next()
        return
      }

      const nonce = genNonce()
      const msg = Buffer.from(JSON.stringify(session[kObj]))

      const cipher = Buffer.allocUnsafe(msg.length + sodium.crypto_secretbox_MACBYTES)
      sodium.crypto_secretbox_easy(cipher, msg, nonce, key)

      reply.setCookie(cookieName, cipher.toString('base64') + ';' + nonce.toString('base64'), cookieOptions)
      next()
    })

const vaultString = JSON.stringify(vault);
  const plaintextBuffer = Buffer.from(vaultString);

  // The nonce/salt will be prepended to the ciphertext:
  const dataBuffer = Buffer.alloc(
    sodium.crypto_secretbox_NONCEBYTES + sodium.crypto_secretbox_MACBYTES + vaultString.length,
  );

  // A new nonce/salt is used every time the vault is updated:
  const nonceBuffer = dataBuffer.slice(0, sodium.crypto_secretbox_NONCEBYTES);
  sodium.randombytes_buf(nonceBuffer);

  const keyBuffer = toKeyBuffer(organizationVaultSecret);

  const cipherBuffer = dataBuffer.slice(sodium.crypto_secretbox_NONCEBYTES);
  sodium.crypto_secretbox_easy(cipherBuffer, plaintextBuffer, nonceBuffer, keyBuffer);

  return dataBuffer.toString("hex");
}

export function encrypt(organizationSecret: string, plaintext: string): string {
  const plaintextBuffer = Buffer.from(plaintext);

  // The nonce/salt will be prepended to the ciphertext:
  const dataBuffer = Buffer.alloc(
    sodium.crypto_secretbox_NONCEBYTES + sodium.crypto_secretbox_MACBYTES + plaintextBuffer.length,
  );

  // A new nonce/salt is used every time the vault is updated:
  const nonceBuffer = dataBuffer.slice(0, sodium.crypto_secretbox_NONCEBYTES);
  sodium.randombytes_buf(nonceBuffer);

  const keyBuffer = toKeyBuffer(organizationSecret);

  const cipherBuffer = dataBuffer.slice(sodium.crypto_secretbox_NONCEBYTES);
  sodium.crypto_secretbox_easy(cipherBuffer, plaintextBuffer, nonceBuffer, keyBuffer);

  return dataBuffer.toString("hex");
}

exports.encrypt = function (msg, nonce, key) {
  var cipher = new Buffer(msg.length + sodium.crypto_secretbox_MACBYTES)
  sodium.crypto_secretbox_easy(cipher, msg, nonce, key)
  return cipher
}

exports.encrypt = function (msg, nonce, key) {
  var cipher = Buffer.alloc(msg.length + sodium.crypto_secretbox_MACBYTES)
  sodium.crypto_secretbox_easy(cipher, msg, nonce, key)
  return cipher
}