feat(HscanStream): adding NOVALUES option (#1943)

* feat(HscanStream): adding NOVALUES option

* fix(Test): adding tests for NOVALUES option

* Update README.md for hscanStream

Co-authored-by: Tihomir Krasimirov Mateev <[email protected]>

---------

Co-authored-by: Nicolas Zambrano <[email protected]>
Co-authored-by: Tihomir Krasimirov Mateev <[email protected]>

Author: 3 people

README.md

@@ -724,12 +724,18 @@ the key names are not utf8 strings.
 There are also `hscanStream`, `zscanStream` and `sscanStream` to iterate through elements in a hash, zset and set. The interface of each is
 similar to `scanStream` except the first argument is the key name:
 
+```javascript
+const stream = redis.zscanStream("myhash", {
+  match: "age:??",
+});
+```
+The `hscanStream` also accepts the `noValues` option to specify whether Redis should return only the keys in the hash table without their corresponding values.
 ```javascript
 const stream = redis.hscanStream("myhash", {
   match: "age:??",
+  noValues: true,
 });
 ```
-
 You can learn more from the [Redis documentation](http://redis.io/commands/scan).
 
 **Useful Tips**

lib/ScanStream.ts

@@ -7,6 +7,7 @@ interface Options extends ReadableOptions {
   command: string;
   redis: any;
   count?: string | number;
+  noValues?: boolean;
 }
 
 /**
@@ -39,7 +40,9 @@ export default class ScanStream extends Readable {
     if (this.opt.count) {
       args.push("COUNT", String(this.opt.count));
     }
-
+    if (this.opt.noValues) {
+      args.push("NOVALUES");
+    }
     this.opt.redis[this.opt.command](args, (err, res) => {
       if (err) {
         this.emit("error", err);

lib/types.ts

@@ -30,4 +30,5 @@ export interface ScanStreamOptions {
   match?: string;
   type?: string;
   count?: number;
-}
+  noValues?: boolean;
+}

test/functional/scan_stream.ts

@@ -161,6 +161,25 @@ describe("*scanStream", () => {
     });
   });
 
+  describe('hscanStream', () => {
+    it('should recognize `NOVALUES`', (done) => {
+      let keys = [];
+      const redis = new Redis();
+      redis.hset('object', 'foo1', 'foo1_value');
+      redis.hset('object', 'foo2', 'foo2_value');
+      redis.hset('object', 'foo3', 'foo3_value');
+      const stream = redis.hscanStream('object', { noValues: true });
+      stream.on('data', function (data) {
+        keys = keys.concat(data);
+      });
+      stream.on('end', () => {
+        expect(keys).to.eql(['foo1', 'foo2', 'foo3']);
+        redis.disconnect();
+        done();
+      });
+    });
+  });
+
   describe("Cluster", () => {
     it("should work in cluster mode", (done) => {
       const slotTable = [