add overall more stability

src/middleware/rateLimit.js

@@ -5,10 +5,26 @@ function pruneBucket(bucket, windowMs, now) {
     }
 }
 
-export function createRateLimiter({windowMs, max, keyGenerator, message}) {
+export function createRateLimiter({windowMs, max, keyGenerator, message, cleanupIntervalMs = 60 * 1000}) {
     const hits = new Map();
+    let cleanupTimer = null;
 
-    return (req, res, next) => {
+    const cleanup = () => {
+        const now = Date.now();
+        for (const [key, bucket] of hits) {
+            pruneBucket(bucket, windowMs, now);
+            if (!bucket.length) {
+                hits.delete(key);
+            }
+        }
+    };
+
+    if (cleanupIntervalMs > 0) {
+        cleanupTimer = setInterval(cleanup, cleanupIntervalMs);
+        cleanupTimer.unref();
+    }
+
+    const limiter = (req, res, next) => {
         const key = keyGenerator(req);
         if (!key) {
             return next();
@@ -17,6 +33,9 @@ export function createRateLimiter({windowMs, max, keyGenerator, message}) {
         const now = Date.now();
         const bucket = hits.get(key) || [];
         pruneBucket(bucket, windowMs, now);
+        if (!bucket.length) {
+            hits.delete(key);
+        }
         if (bucket.length >= max) {
             return res.status(429).json({error: message});
         }
@@ -25,4 +44,14 @@ export function createRateLimiter({windowMs, max, keyGenerator, message}) {
         hits.set(key, bucket);
         return next();
     };
+
+    limiter.close = () => {
+        if (cleanupTimer) {
+            clearInterval(cleanupTimer);
+            cleanupTimer = null;
+        }
+        hits.clear();
+    };
+
+    return limiter;
 }