Implement API Request Retry with Exponential Backoff

async function fetchWithRetry(url, options = {}, retries = 3, delay = 1000) {
    let lastError;
    for (let i = 0; i < retries; i++) {
        try {
            const response = await fetch(url, options);
            if (!response.ok && response.status !== 429) { // Exclude 429 for simple retry, handle explicitly if needed
                throw new Error(`HTTP error! Status: ${response.status}`);
            }
            return response; // Success!
        } catch (error) {
            lastError = error;
            console.warn(`Attempt ${i + 1} failed: ${error.message}. Retrying in ${delay}ms...`);
            await new Promise(resolve => setTimeout(resolve, delay));
            delay *= 2; // Exponential backoff
        }
    }
    throw new Error(`Max retries (${retries}) exceeded. Last error: ${lastError ? lastError.message : 'Unknown error'}`);
}

// Example usage:
// fetchWithRetry('https://api.example.com/unreliable-endpoint', { method: 'GET' }, 5, 500)
//     .then(response => response.json())
//     .then(data => console.log('Successfully fetched data after retries:', data))
//     .catch(error => console.error('Failed after all retries:', error.message));

// // Simulate a failing endpoint that eventually succeeds
// let callCount = 0;
// const mockFetch = async (url, options) => {
//     callCount++;
//     if (callCount < 3) { // Fail first 2 attempts
//         console.log(`Mock fetch attempt ${callCount}: Failing`);
//         throw new Error('Simulated network error');
//     }
//     console.log(`Mock fetch attempt ${callCount}: Succeeding`);
//     return new Response(JSON.stringify({ message: 'Success!' }), { status: 200, headers: { 'Content-Type': 'application/json' } });
// };
// global.fetch = mockFetch; // Temporarily override global fetch for demonstration
// fetchWithRetry('https://api.example.com/unreliable-endpoint', {}, 5, 200)
//     .then(response => response.json())
//     .then(data => console.log('Mock Data:', data))
//     .catch(error => console.error('Mock Failed:', error.message));
// delete global.fetch; // Clean up