API Reference

createCache(config)

The main entry point for initializing the caching layer.

Option	Type	Default	Description
adapter	CacheClient	—	Required. Storage adapter (Memory, Redis, Memcached).
staleTime	number	60	Seconds data stays fresh (TanStack: staleTime).
gcTime	number	300	Seconds stale data stays in cache (TanStack: gcTime).
swr	boolean	false	Enable background revalidation.
stampede	boolean	true	Prevent "thundering herd" via request coalescing.
vary	string[]	[]	Headers to namespace caches (e.g., ['Authorization']).
sortQuery	boolean	false	Sort query params alphabetically for higher hit rates.
maxBodySize	number	2097152	Max response size in bytes (default: 2MB).
autoInvalidate	boolean	false	Auto-invalidate route patterns on successful mutations.
retry	number	0	Number of retries with exponential backoff (fetch only).
keyPrefix	string	"erc:"	Global prefix for all cache keys in Redis/Memcached.
enabled	boolean	true	Toggle caching globally.
key	string | fn	—	(Route only) Manual key override (string or (req) => string).

Returns

• middleware(): Global Express middleware.
• route(options): Per-route middleware with overrides.
• fetch(key, fetcher, options): Standalone data caching method.
• invalidate(...patterns): Middleware to trigger invalidation.
• invalidateRoute(...patterns): Programmatic invalidation method.
• adapter: The underlying storage adapter instance.

---

cache.route(overrides)

Use this to apply specific caching rules to individual routes.

app.get('/heavy-report', cache.route({ 
  staleTime: 3600, // 1 hour
  swr: true 
}), handler);

---

cache.fetch(key, fetcher, options)

Standalone method for manual data caching. Includes full SWR, Stampede Protection, and Retries.

const data = await cache.fetch('my-key', async () => {
  return await db.users.findMany();
}, { 
  staleTime: 60, 
  swr: true, 
  retry: 3 
});

---

cache.invalidate(...patterns)

Express middleware that increments the epoch version for specific patterns upon successful (2xx) response.

app.post('/api/posts', cache.invalidate('/api/posts'), createPost);

---

cache.invalidateRoute(...patterns)

A programmatic way to invalidate routes from outside an Express request context.

await cache.invalidateRoute('/api/users/123');