export function b64uEncode(buf: Buffer | Uint8Array): string {
  const b = Buffer.isBuffer(buf) ? buf : Buffer.from(buf);
  return b
    .toString('base64')
    .replace(/\+/g, '-')
    .replace(/\//g, '_')
    .replace(/=+$/, '');
}

export function b64uDecode(value: string): Buffer {
  const padded = value.replace(/-/g, '+').replace(/_/g, '/');
  const padLen = (4 - (padded.length % 4)) % 4;
  return Buffer.from(padded + '='.repeat(padLen), 'base64');
}