Support RedisTimeSeries (#1757)

* Implement missing commands and add test

* Update DECRBY.spec.ts

* Small changes

* clean code

* Update MGET_WITHLABELS.ts

Use map in transformReply

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

packages/time-series/lib/commands/GET.spec.ts

@@ -0,0 +1,35 @@
+import { strict as assert } from 'assert';
+import testUtils, { GLOBAL } from '../test-utils';
+import { transformArguments } from './GET';
+
+describe('GET', () => {
+    it('transformArguments', () => {
+        assert.deepEqual(
+            transformArguments('key'),
+            ['TS.GET', 'key']
+        );
+    });
+
+    describe('client.ts.get', () => {
+        testUtils.testWithClient('null', async client => {
+            await client.ts.create('key');
+
+            assert.equal(
+                await client.ts.get('key'),
+                null
+            );
+        }, GLOBAL.SERVERS.OPEN);
+
+        testUtils.testWithClient('with samples', async client => {
+            await client.ts.add('key', 0, 1);
+
+            assert.deepEqual(
+                await client.ts.get('key'),
+                {
+                    timestamp: 0,
+                    value: 1
+                }
+            );
+        }, GLOBAL.SERVERS.OPEN);
+    });
+});