Error Handling

async function makeApiRequest(endpoint, options = {}) {
  try {
    const response = await fetch(`${API_BASE}${endpoint}`, {
      ...options,
      headers: {
        'Authorization': `Bearer ${API_KEY}`,
        'Content-Type': 'application/json',
        ...options.headers
      }
    });

    const data = await response.json();

    if (!response.ok) {
      // Handle different error types
      switch (data.error?.type) {
        case 'authentication_error':
          throw new AuthError(data.error.message);
        
        case 'validation_error':
          throw new ValidationError(data.error.message, data.error.errors);
        
        case 'rate_limit_error':
          const retryAfter = data.error.retry_after || 60;
          throw new RateLimitError(data.error.message, retryAfter);
        
        default:
          throw new ApiError(data.error.message, data.error.code);
      }
    }

    return data;
  } catch (error) {
    // Handle network errors
    if (error instanceof TypeError) {
      throw new NetworkError('Network request failed');
    }
    throw error;
  }
}

// Usage with retry logic
async function createInvoiceWithRetry(invoiceData, maxRetries = 3) {
  for (let i = 0; i < maxRetries; i++) {
    try {
      return await makeApiRequest('/invoices', {
        method: 'POST',
        body: JSON.stringify(invoiceData)
      });
    } catch (error) {
      if (error instanceof RateLimitError) {
        // Wait and retry
        await sleep(error.retryAfter * 1000);
        continue;
      }
      
      if (error instanceof ApiError && i < maxRetries - 1) {
        // Exponential backoff for server errors
        await sleep(Math.pow(2, i) * 1000);
        continue;
      }
      
      throw error;
    }
  }
}