atikin-cache-ninja/index.js

A smart caching utility that optimizes app performance by providing in-memory caching with expiry, automatic invalidation, and async support.

const { EventEmitter } = require("events");

class CacheNinja extends EventEmitter {
  constructor(strategy = "LRU", maxSize = 100) {
    super();
    this.cache = new Map();
    this.strategy = strategy;
    this.maxSize = maxSize;
    this.hitCount = 0;
    this.missCount = 0;
  }

  // Set a cache entry with optional TTL (Time to Live)
  set(key, value, ttl = null) {
    if (this.cache.size >= this.maxSize) {
      this.evict();
    }

    const entry = { value, expiry: ttl ? Date.now() + ttl : null };
    this.cache.set(key, entry);

    if (ttl) {
      setTimeout(() => this.cache.delete(key), ttl);
    }

    return this;
  }

  // Get a cache entry
  get(key) {
    const entry = this.cache.get(key);

    if (!entry) {
      this.missCount++;
      this.emit("cacheMiss", key);
      return null;
    }

    if (entry.expiry && Date.now() > entry.expiry) {
      this.cache.delete(key);
      this.missCount++;
      this.emit("cacheMiss", key);
      return null;
    }

    this.hitCount++;
    this.emit("cacheHit", key);
    return entry.value;
  }

  // Evict an entry based on strategy
  evict() {
    let key;
    if (this.strategy === "FIFO") {
      key = this.cache.keys().next().value;
    } else if (this.strategy === "LRU") {
      key = [...this.cache.keys()].reduce((a, b) =>
        this.cache.get(a).expiry < this.cache.get(b).expiry ? a : b
      );
    }

    this.cache.delete(key);
  }

  // Get cache stats
  getStats() {
    return {
      hits: this.hitCount,
      misses: this.missCount,
      size: this.cache.size,
    };
  }

  // Clear the cache
  clear() {
    this.cache.clear();
    this.hitCount = 0;
    this.missCount = 0;
  }
}

module.exports = CacheNinja;