Exploration of Client Side Caching support

packages/client/lib/RESP/types.ts

@@ -263,7 +263,13 @@ export type CommandArguments = Array<RedisArgument> & { preserve?: unknown };
 //   response?: ResponsePolicies | null;
 // };
 
+export interface CacheInfo {
+  cacheKey: string;
+  redisKeys: Array<string>
+}
+
 export type Command = {
+  name?: () => string;
   FIRST_KEY_INDEX?: number | ((this: void, ...args: Array<any>) => RedisArgument | undefined);
   IS_READ_ONLY?: boolean;
   /**
@@ -275,6 +281,7 @@ export type Command = {
   transformArguments(this: void, ...args: Array<any>): CommandArguments;
   TRANSFORM_LEGACY_REPLY?: boolean;
   transformReply: TransformReply | Record<RespVersions, TransformReply>;
+  getCacheInfo?: (...args: Array<any>) => CacheInfo | undefined;
 };
 
 export type RedisCommands = Record<string, Command>;

packages/client/lib/client/README-cache.md

@@ -0,0 +1,64 @@
+# Client Side Caching Support
+
+Client Side Caching enables Redis Servers and Clients to work together to enable a client to cache results from command sent to a server and be informed by the server when the cached result is no longer valid.
+
+## Usage
+
+node-redis supports two ways of instantiating client side caching support
+
+Note: Client Side Caching is only supported with RESP3.
+
+### Anonymous Cache
+
+```javascript
+const client = createClient({RESP: 3, clientSideCache: {ttl: 0, maxEntries: 0, lru: false}})
+```
+
+In this instance, the cache is opaque to the user, and they have no control over it.
+
+### Controllable Cache
+
+```javascript
+const ttl = 0, maxEntries = 0, lru = false;
+const cache = new BasicClientSideCache(ttl, maxEntries, lru);
+const client = createClient({RESP: 3, clientSideCache: cache});
+```
+
+In this instance, the user has full control over the cache, as they have access to the cache object.
+
+They can manually invalidate keys
+
+```javascript
+cache.invalidate(key);
+```
+
+they can clear the entire cache
+g
+```javascript
+cache.clear();
+```
+
+as well as get cache metrics
+
+```typescript
+const hits: number = cache.cacheHits();
+const misses: number = cache.cacheMisses();
+```
+
+## Pooled Caching
+
+Similar to individual clients, node-redis also supports caching for its pooled client object, with the cache being able to be instantiated in an anonymous manner or a controllable manner.
+
+### Anonymous Cache
+
+```javascript
+const client = createClientPool({RESP: 3}, {clientSideCache: {ttl: 0, maxEntries: 0, lru: false}, minimum: 8});
+```
+
+### Controllable Cache
+
+```javascript
+const ttl = 0, maxEntries = 0, lru = false;
+const cache = new BasicPooledClientSideCache(ttl, maxEntries, lru);
+const client = createClientPool({RESP: 3}, {clientSideCache: cache, minimum: 8});
+```