Cache NodeId and Location (#35)

* Cache NodeId and Location
* Fix frontend dependency vuln

packages/backend/src/nodeId.ts

@@ -0,0 +1,55 @@
+import { timestamp, Maybe, Types, idGenerator } from '@dotstats/common';
+
+const CACHE_LIFETIME = (24 * 3600 * 1000) as Types.Milliseconds; // 24h
+const CACHE_INTERVAL = (3600 * 1000) as Types.Milliseconds; // 1h
+
+interface NodeIdCache {
+  id: Types.NodeId;
+  ts: Types.Timestamp;
+}
+
+const nextId = idGenerator<Types.NodeId>();
+const idCache = new Map<Types.NodePubKey, NodeIdCache>();
+
+function clearCache() {
+  const now = timestamp();
+
+  for (const [pubkey, { ts }] of idCache.entries()) {
+    if ((now - ts) > CACHE_LIFETIME) {
+      idCache.delete(pubkey);
+    }
+  }
+
+  setTimeout(clearCache, CACHE_INTERVAL);
+}
+
+clearCache();
+
+export function getId(pubkey: Maybe<Types.NodePubKey>): Types.NodeId {
+  if (!pubkey) {
+    return nextId();
+  }
+
+  const cached = idCache.get(pubkey);
+
+  if (cached) {
+    return cached.id;
+  }
+
+  const id = nextId();
+  const ts = timestamp();
+
+  idCache.set(pubkey, { id, ts });
+
+  return id;
+}
+
+export function refreshId(pubkey: Maybe<Types.NodePubKey>, id: Types.NodeId) {
+  if (!pubkey) {
+    return;
+  }
+
+  const ts = timestamp();
+
+  idCache.set(pubkey, { id, ts });
+}