add ZDiffStore command (#1775)

Author: MrChenCode

commands.go

@@ -281,6 +281,7 @@ type Cmdable interface {
 	ZRandMember(ctx context.Context, key string, count int, withScores bool) *StringSliceCmd
 	ZDiff(ctx context.Context, keys ...string) *StringSliceCmd
 	ZDiffWithScores(ctx context.Context, keys ...string) *ZSliceCmd
+	ZDiffStore(ctx context.Context, destination string, keys ...string) *IntCmd
 
 	PFAdd(ctx context.Context, key string, els ...interface{}) *IntCmd
 	PFCount(ctx context.Context, keys ...string) *IntCmd
@@ -2458,6 +2459,18 @@ func (c cmdable) ZDiffWithScores(ctx context.Context, keys ...string) *ZSliceCmd
 	return cmd
 }
 
+// redis-server version >=6.2.0.
+func (c cmdable) ZDiffStore(ctx context.Context, destination string, keys ...string) *IntCmd {
+	args := make([]interface{}, 0, 3+len(keys))
+	args = append(args, "zdiffstore", destination, len(keys))
+	for _, key := range keys {
+		args = append(args, key)
+	}
+	cmd := NewIntCmd(ctx, args...)
+	_ = c(ctx, cmd)
+	return cmd
+}
+
 //------------------------------------------------------------------------------
 
 func (c cmdable) PFAdd(ctx context.Context, key string, els ...interface{}) *IntCmd {

commands_test.go

@@ -4048,6 +4048,31 @@ var _ = Describe("Commands", func() {
 				},
 			}))
 		})
+
+		It("should ZDiffStore", func() {
+			err := client.ZAdd(ctx, "zset1", &redis.Z{Score: 1, Member: "one"}).Err()
+			Expect(err).NotTo(HaveOccurred())
+			err = client.ZAdd(ctx, "zset1", &redis.Z{Score: 2, Member: "two"}).Err()
+			Expect(err).NotTo(HaveOccurred())
+			err = client.ZAdd(ctx, "zset2", &redis.Z{Score: 1, Member: "one"}).Err()
+			Expect(err).NotTo(HaveOccurred())
+			err = client.ZAdd(ctx, "zset2", &redis.Z{Score: 2, Member: "two"}).Err()
+			Expect(err).NotTo(HaveOccurred())
+			err = client.ZAdd(ctx, "zset2", &redis.Z{Score: 3, Member: "three"}).Err()
+			Expect(err).NotTo(HaveOccurred())
+			v, err := client.ZDiffStore(ctx, "out1", "zset1", "zset2").Result()
+			Expect(err).NotTo(HaveOccurred())
+			Expect(v).To(Equal(int64(0)))
+			v, err = client.ZDiffStore(ctx, "out1", "zset2", "zset1").Result()
+			Expect(err).NotTo(HaveOccurred())
+			Expect(v).To(Equal(int64(1)))
+			vals, err := client.ZRangeWithScores(ctx, "out1", 0, -1).Result()
+			Expect(err).NotTo(HaveOccurred())
+			Expect(vals).To(Equal([]redis.Z{{
+				Score:  3,
+				Member: "three",
+			}}))
+		})
 	})
 
 	Describe("streams", func() {