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How would you implement caching in a Node.js application?

Q: How would you implement caching in a Node.js application?

**TL;DR.** Cache to avoid recomputing or refetching expensive results. Choose a tier: **in-process** (a Map/LRU — fastest, per-instance) or **shared** (Redis — consistent across instances). Apply a strategy (**cache-aside** is most common), set **TTLs**, and have an **invalidation** plan. The hard parts are **staleness** and **invalidation**, not storage. request cache? hit → return <text

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This question probes into strategies for improving application responsiveness and reducing database load.

cachingperformanceredisoptimization

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Cache-aside with Redis

async function getProduct(id) {
  const key = 'product:' + id;
  const cached = await redis.get(key);
  if (cached) return JSON.parse(cached);          // hit

  const product = await db.product(id);           // miss → load
  await redis.set(key, JSON.stringify(product), 'EX', 300); // TTL 5m
  return product;
}
// On update: await redis.del('product:' + id);   // invalidate

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