# Memory Cache vs lru-cache The Canonical LRU vs a Batteries-Included Cache ## Overview Compare lru-cache and @humanspeak/memory-cache: the canonical LRU implementation against a TypeScript cache that layers wildcard invalidation, lifecycle hooks, statistics, and a @cached decorator on top of LRU + TTL. - **Memory Cache site:** https://memory.svelte.page - **Memory Cache npm:** https://www.npmjs.com/package/%40humanspeak%2Fmemory-cache - **Memory Cache slug:** memory-cache - **Category:** LRU Cache - **Approach:** Highly optimized bounded map with recency tracking, size-aware eviction, and async fetch() - **GitHub:** https://github.com/isaacs/node-lru-cache - **npm:** https://www.npmjs.com/package/lru-cache ## Feature comparison | Feature | @humanspeak/memory-cache | lru-cache | Notes | | --- | --- | --- | --- | | Zero Dependencies | Yes | Yes | | | TypeScript Support | Written in TypeScript | Written in TypeScript | | | LRU Eviction | Yes | Yes | lru-cache is the canonical, heavily tuned implementation. Memory Cache prunes expired entries before evicting any valid least-recently-used key. | | TTL Expiration | Per cache instance | Per cache + per-entry overrides | lru-cache also supports allowStale and updateAgeOnGet for finer recency/staleness control. | | Size-Aware Eviction | Entry count + computed weight (maxSize + maxWeight / sizeCalculation) | Entry count + computed size (max + maxSize / sizeCalculation) | Both accept a user-supplied calculator. Memory Cache exposes aggregate weight in getStats(); lru-cache has broader size and disposal tuning. | | Wildcard / Prefix Deletion | deleteByMagicString + deleteByPrefix | No | | | Method Memoization Decorator | @cached, async-aware | memo() method (no decorator) | | | Async Fetch De-Duplication | getOrSet() collapses concurrent lookups | fetch() with fetchMethod | | | Stale-While-Revalidate | No | allowStale + background fetch | | | Lifecycle Instrumentation | Six lifecycle hooks | dispose / onInsert callbacks | | | Built-In Statistics | getStats() aggregate counters | Opt-in per-call status tracking | | | Browser Support | Yes | Yes | | ## Memory Cache strengths - Zero runtime dependencies — works in Node and the browser - TypeScript-first with fully typed generics (MemoryCache) - TTL expiration and true LRU eviction in one cache — expired entries are pruned before any valid key is evicted - Wildcard + prefix bulk invalidation (deleteByMagicString, deleteByPrefix) - @cached decorator for method-level memoization — async-aware with in-flight de-duplication - getOrSet() async fetch helper that de-duplicates concurrent lookups for the same key - Lifecycle hooks (onHit, onMiss, onSet, onDelete, onExpire, onEvict) plus built-in getStats() - Synchronous reads and writes — no await on the hot path ## lru-cache strengths - The canonical LRU — extremely optimized and battle-tested at npm scale - Broader size-calculation, disposal, and tuning controls - Stale-while-revalidate patterns with allowStale and async fetch() - Rich low-level controls (peek, dispose, updateAgeOnGet, per-entry TTL) ## Memory Cache limitations - Smaller community (newer project) - In-process only — no persistence or multi-process sharing by design - TTL is configured per cache instance, not per entry ## lru-cache limitations - Lower-level API with many knobs to hold correctly - No wildcard or prefix bulk invalidation - Memoization is a method helper, not a decorator you can put on class methods - No aggregate hit/miss statistics or lifecycle hook set out of the box ## Verdict Both libraries can enforce application-defined computed-weight bounds; neither automatically measures retained JavaScript heap. If your bottleneck is raw LRU throughput or you need stale-while-revalidate and extensive low-level tuning, lru-cache remains the reference implementation. Memory Cache adds a @cached decorator, wildcard invalidation, lifecycle hooks, and aggregate stats with a smaller API surface. Pick lru-cache for infrastructure-grade controls; pick Memory Cache when you want application-level caching that reads like TypeScript. ## Keywords lru-cache alternative, lru-cache vs memory-cache, lru cache typescript, lru cache decorator, javascript cache library, bounded cache node.js