Reference

try {
  const result = await contract.call();
  return { success: true, data: result };
} catch (error) {
  if (isRetryable(error)) {
    return retry(contract.call, { maxAttempts: 3 });
  }
  throw new AppError(ErrorCode.CONTRACT_CALL_FAILED, error);
}

function verifyWebhook(payload: string, signature: string): boolean {
  const expected = crypto
    .createHmac('sha256', secret)
    .update(payload)
    .digest('hex');
  return timingSafeEqual(
    Buffer.from(signature),
    Buffer.from(expected)
  );
}

const { address, isConnected, chain } = useAccount();
const { connect, disconnect } = useConnect();

useEffect(() => {
  if (isConnected && address) {
    syncUserSession(address, chain?.id);
  }
}, [isConnected, address, chain?.id]);

async function withRetry<T>(
  fn: () => Promise<T>,
  opts = { maxAttempts: 3 }
): Promise<T> {
  let last: unknown;
  for (let i = 0; i < opts.maxAttempts; i++) {
    try {
      return await fn();
    } catch (e) {
      last = e;
      if (i < opts.maxAttempts - 1) await delay(1000 * (i + 1));
    }
  }
  throw last;
}