Errors

{
  "code": 1001,
  "message": "Parameter 'power' must be positive",
  "details": {
    "field": "power",
    "value": -5
  }
}

async function callWithRetry(fn: () => Promise<Response>, maxAttempts = 5) {
  for (let attempt = 0; attempt < maxAttempts; attempt++) {
    const res = await fn();
    if (res.ok) return res;

    const body = await res.json().catch(() => null);
    const code = body?.code;

    // Token expired — refresh and retry once
    if (code === 2002 && attempt === 0) {
      await refreshToken();
      continue;
    }

    // Rate-limited or transient server error — backoff and retry
    if (code === 5001 || code === 9001) {
      const delay = Math.min(1000 * 2 ** attempt, 30_000);
      const jitter = Math.random() * 0.3 * delay;
      await new Promise(r => setTimeout(r, delay + jitter));
      continue;
    }

    // Anything else is a permanent error — surface to caller
    throw new ApiError(code, body?.message);
  }
  throw new Error('Max retry attempts exceeded');
}