typescriptapifetchnetworkretry

Fetch with Retry

Fetch wrapper with exponential backoff retry logic. Handles transient network errors gracefully.

Code

interface RetryOptions {
  maxRetries?: number;
  baseDelay?: number;
  maxDelay?: number;
}

async function fetchWithRetry(
  url: string,
  options?: RequestInit,
  retryOptions: RetryOptions = {}
): Promise<Response> {
  const { maxRetries = 3, baseDelay = 1000, maxDelay = 10000 } = retryOptions;

  let lastError: Error;

  for (let attempt = 0; attempt <= maxRetries; attempt++) {
    try {
      const response = await fetch(url, options);

      // Retry on 5xx errors
      if (response.status >= 500 && attempt < maxRetries) {
        throw new Error(`Server error: ${response.status}`);
      }

      return response;
    } catch (error) {
      lastError = error instanceof Error ? error : new Error(String(error));

      if (attempt < maxRetries) {
        // Exponential backoff with jitter
        const delay = Math.min(baseDelay * Math.pow(2, attempt), maxDelay);
        const jitter = delay * 0.1 * Math.random();
        await new Promise(r => setTimeout(r, delay + jitter));
      }
    }
  }

  throw lastError!;
}

// Usage
const response = await fetchWithRetry('/api/data', {
  method: 'GET',
}, { maxRetries: 5 });