Added sorted set example. (#2005)

* Added sorted set example.

* Update sorted-set.js

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

examples/sorted-set.js

@@ -0,0 +1,35 @@
+// Add several values with their scores to a Sorted Set,
+// then retrieve them all using ZSCAN.
+
+import { createClient } from 'redis';
+
+async function addToSortedSet() {
+  const client = createClient();
+  await client.connect();
+
+  await client.zAdd('mysortedset', [
+    {
+      score: 99,
+      value: 'Ninety Nine'
+    },
+    {
+      score: 100,
+      value: 'One Hundred'
+    },
+    {
+      score: 101,
+      value: 'One Hundred and One'
+    }
+  ]);
+
+  // Get all of the values/scores from the sorted set using
+  // the scan approach:
+  // https://redis.io/commands/zscan
+  for await (const memberWithScore of client.zScanIterator('mysortedset')) {
+    console.log(memberWithScore);
+  }
+  
+  await client.quit();
+}
+
+addToSortedSet();