Support COMMAND GETKEYSANDFLAGS (#2039)

* Support COMMAND GETKEYSANDFLAGS

* Update COMMAND_GETKEYSANDFLAGS.spec.ts

remove '.only'

* clean code

Co-authored-by: leibale <leibale1998@gmail.com>

packages/client/lib/commands/COMMAND_GETKEYSANDFLAGS.ts

@@ -0,0 +1,24 @@
+import { RedisCommandArgument, RedisCommandArguments } from '.';
+
+export const IS_READ_ONLY = true;
+
+export function transformArguments(args: Array<RedisCommandArgument>): RedisCommandArguments {
+    return ['COMMAND', 'GETKEYSANDFLAGS', ...args];
+}
+
+type KeysAndFlagsRawReply = Array<[
+    RedisCommandArgument,
+    RedisCommandArguments
+]>;
+
+type KeysAndFlagsReply = Array<{
+    key: RedisCommandArgument;
+    flags: RedisCommandArguments;
+}>;
+
+export function transformReply(reply: KeysAndFlagsRawReply): KeysAndFlagsReply {
+    return reply.map(([key, flags]) => ({
+        key,
+        flags
+    }));
+}