interface CacheEntry<T> {
value: T;
expiry: number;
}
export class MemoryCache<T> {
private cache = new Map<string, CacheEntry<T>>();
private defaultTTL: number;
constructor(defaultTTLMs: number = 5 * 60 * 1000) { // 5 minutes default
this.defaultTTL = defaultTTLMs;
// Cleanup expired entries every minute
if (typeof setInterval !== 'undefined') {
setInterval(() => {
this.cleanup();
}, 60 * 1000);
}
}
set(key: string, value: T, ttlMs?: number): void {
const expiry = Date.now() + (ttlMs || this.defaultTTL);
this.cache.set(key, { value, expiry });
}
get(key: string): T | null {
const entry = this.cache.get(key);
if (!entry) {
return null;
}
if (Date.now() > entry.expiry) {
this.cache.delete(key);
return null;
}
return entry.value;
}
delete(key: string): boolean {
return this.cache.delete(key);
}
clear(): void {
this.cache.clear();
}
size(): number {
return this.cache.size;
}
private cleanup(): void {
const now = Date.now();
for (const [key, entry] of this.cache.entries()) {
if (now > entry.expiry) {
this.cache.delete(key);
}
}
}
// Get cache hit/miss stats
getStats() {
return {
size: this.cache.size,
defaultTTL: this.defaultTTL
};
}
}
// Create cache instances for different data types
export const routeCache = new MemoryCache(5 * 60 * 1000); // 5 minutes for routes
export const isochroneCache = new MemoryCache(10 * 60 * 1000); // 10 minutes for isochrones
export const healthCache = new MemoryCache(30 * 1000); // 30 seconds for health checks
