isaacs/node-lru-cache
Node Lru Cache
node-lru-cache is a key-value store for Node.js that implements a memory-limited cache. It prevents memory exhaustion by capping the total number of items or total byte size, automatically evicting the least-recently-used items to maintain these limits.
The project provides specialized caching patterns, including time-to-live durations to ensure data freshness and a stale-while-revalidate mechanism that serves expired content while asynchronously fetching updates in the background. It also includes diagnostic tools for monitoring cache hits, misses, and eviction metrics through operational status objects and diagnostic channels.
The implementation covers broader memory management and data recovery capabilities, such as automatic data fetching for missing entries, manual pruning of outdated items, and the execution of cleanup functions when items expire to release external resources.
Features
- Memory-Limited Caches - Implements a memory-limited key-value store that prevents exhaustion by capping item counts or total byte size.
- LRU Cache Eviction - Implements a memory-limited cache that automatically evicts the least-recently-used items to prevent memory exhaustion.
- Cache Eviction Policies - Implements size-based eviction algorithms to maintain memory limits by removing the oldest items.
- Least Recently Used Caches - Prevents application crashes by capping memory usage through an automatic least-recently-used eviction policy.
- Application Caching - Stores frequently accessed application data in memory to reduce latency and database load.
- Hash Maps - Utilizes a hash map to provide constant-time retrieval of cached entries and their associated tracking nodes.
- Linked-List LRU Evictions - Uses a doubly linked list to maintain access order for efficient least-recently-used item eviction.
- Time-To-Live Expirations - Implements automatic data expiration based on configurable time-to-live durations.
- Cache Memory Limits - Enforces memory constraints by blocking items that exceed a calculated size from entering the cache.
- Resource Disposal - Provides mechanisms for disposing of resources and executing cleanup functions when items are removed.
- Eviction Callbacks - Implements hooks that execute custom cleanup logic when cache entries are evicted or expire.
- Resource Lifecycle Management - Ensures the release of external system resources through cleanup logic executed upon item expiration.
- Cache Performance Monitoring - Tracks hit ratios, misses, and eviction metrics to analyze and optimize caching efficiency.
- Diagnostic Channels - Provides internal event publishing via diagnostic channels for real-time observability of cache performance metrics.
- Data Fetching - Automates data recovery by retrieving values through a specified method when a key is missing.
- Stale-While-Revalidate - Supports the stale-while-revalidate pattern to serve expired content while asynchronously updating entries.
- Caching - LRU cache implementation.
