rename to client

greyscale/src/cache.js

@@ -0,0 +1,62 @@
+export class APICache {
+    constructor({ maxSize = 250, ttl = 1000 * 60 * 20 } = {}) {
+        this.maxSize = maxSize;
+        this.ttl = ttl;
+        this.store = new Map();
+    }
+
+    makeKey(namespace, key) {
+        return `${namespace}:${String(key)}`;
+    }
+
+    isExpired(entry) {
+        return !entry || Date.now() - entry.ts > entry.ttl;
+    }
+
+    pruneToSize() {
+        if (this.store.size <= this.maxSize) return;
+        const entries = [...this.store.entries()].sort((a, b) => a[1].ts - b[1].ts);
+        const overflow = this.store.size - this.maxSize;
+        for (let i = 0; i < overflow; i += 1) {
+            this.store.delete(entries[i][0]);
+        }
+    }
+
+    async get(namespace, key) {
+        const cacheKey = this.makeKey(namespace, key);
+        const entry = this.store.get(cacheKey);
+        if (!entry) return null;
+        if (this.isExpired(entry)) {
+            this.store.delete(cacheKey);
+            return null;
+        }
+        return entry.value;
+    }
+
+    async set(namespace, key, value, ttl = this.ttl) {
+        const cacheKey = this.makeKey(namespace, key);
+        this.store.set(cacheKey, { value, ts: Date.now(), ttl });
+        this.pruneToSize();
+    }
+
+    clearExpired() {
+        for (const [key, entry] of this.store.entries()) {
+            if (this.isExpired(entry)) this.store.delete(key);
+        }
+    }
+
+    async clear() {
+        this.store.clear();
+    }
+
+    getCacheStats() {
+        const namespaces = new Set();
+        for (const key of this.store.keys()) namespaces.add(key.split(':', 1)[0]);
+        return {
+            size: this.store.size,
+            namespaces: [...namespaces],
+            maxSize: this.maxSize,
+            ttlMs: this.ttl,
+        };
+    }
+}