fix: type of zscore result should be nullable (#1639)

Author: vimutti77

Diff for: bin/returnTypes.js

@@ -317,7 +317,7 @@ module.exports = {
   zrevrange: "string[]",
   zrevrangebyscore: "string[]",
   zrevrank: "number | null",
-  zscore: "string",
+  zscore: "string | null",
   zunion: "string[]",
   zmscore: "(string | null)[]",
   zunionstore: "number",

Diff for: lib/utils/RedisCommander.ts

@@ -13854,13 +13854,13 @@ interface RedisCommander<Context extends ClientContext = { type: "default" }> {
   zscore(
     key: RedisKey,
     member: string | Buffer | number,
-    callback?: Callback<string>
-  ): Result<string, Context>;
+    callback?: Callback<string | null>
+  ): Result<string | null, Context>;
   zscoreBuffer(
     key: RedisKey,
     member: string | Buffer | number,
-    callback?: Callback<Buffer>
-  ): Result<Buffer, Context>;
+    callback?: Callback<Buffer | null>
+  ): Result<Buffer | null, Context>;
 
   /**
    * Add multiple sorted sets

Diff for: test/typing/commands.test-d.ts

@@ -88,6 +88,10 @@ expectType<Promise<number>>(redis.zadd("key", "CH", 1, "member"));
 expectType<Promise<string | null>>(redis.zrandmember("key"));
 expectType<Promise<string[]>>(redis.zrandmember("key", 20));
 
+// ZSCORE
+expectType<Promise<string | null>>(redis.zscore("key", "member"));
+expectType<Promise<Buffer | null>>(redis.zscoreBuffer("key", "member"));
+
 // GETRANGE
 expectType<Promise<Buffer>>(redis.getrangeBuffer("foo", 0, 1));