Cache API Responses with a Time-to-Live (TTL)

const axios = require('axios');

const apiCache = new Map(); // Stores { url: { data, timestamp, ttl } }

/**
 * Fetches data from an API, caching the response for a specified TTL.
 * @param {string} url The API endpoint URL.
 * @param {number} ttlSeconds Time-to-live for the cache entry in seconds.
 * @returns {Promise<any>} The API response data.
 */
async function fetchWithCache(url, ttlSeconds = 60) {
    const now = Date.now();
    const cachedEntry = apiCache.get(url);

    if (cachedEntry && (now - cachedEntry.timestamp) < (cachedEntry.ttl * 1000)) {
        console.log(`Cache hit for ${url}`);
        return cachedEntry.data;
    }

    console.log(`Cache miss for ${url}. Fetching from API...`);
    try {
        const response = await axios.get(url);
        const data = response.data;
        apiCache.set(url, { data, timestamp: now, ttl: ttlSeconds });
        return data;
    } catch (error) {
        console.error(`Error fetching ${url}:`, error.message);
        throw error;
    }
}

// --- Example Usage ---
(async () => {
    const API_ENDPOINT = 'https://jsonplaceholder.typicode.com/todos/1';

    console.log('--- First call (cache miss) ---');
    let data1 = await fetchWithCache(API_ENDPOINT, 5); // Cache for 5 seconds
    console.log('Data 1:', data1.title);

    console.log('
--- Second call (cache hit) ---');
    let data2 = await fetchWithCache(API_ENDPOINT, 5);
    console.log('Data 2:', data2.title);

    console.log('
--- Waiting for cache to expire ---');
    await new Promise(resolve => setTimeout(resolve, 6000)); // Wait 6 seconds

    console.log('
--- Third call (cache miss after expiration) ---');
    let data3 = await fetchWithCache(API_ENDPOINT, 5);
    console.log('Data 3:', data3.title);

    console.log('
--- Another endpoint with different TTL ---');
    const ANOTHER_ENDPOINT = 'https://jsonplaceholder.typicode.com/posts/1';
    let data4 = await fetchWithCache(ANOTHER_ENDPOINT, 2); // Cache for 2 seconds
    console.log('Data 4:', data4.title);

    await new Promise(resolve => setTimeout(resolve, 1000));

    console.log('
--- Cache hit for another endpoint ---');
    let data5 = await fetchWithCache(ANOTHER_ENDPOINT, 2);
    console.log('Data 5:', data5.title);
})();