Support new cluster commands (#2050)

* Support new cluster commands

* clean code

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

packages/client/lib/commands/CLUSTER_LINKS.spec.ts

@@ -0,0 +1,27 @@
+import { strict as assert } from 'assert';
+import testUtils, { GLOBAL } from '../test-utils';
+import { transformArguments } from './CLUSTER_LINKS';
+
+describe('CLUSTER LINKS', () => {
+    testUtils.isVersionGreaterThanHook([7, 0]);
+
+    it('transformArguments', () => {
+        assert.deepEqual(
+            transformArguments(),
+            ['CLUSTER', 'LINKS']
+        );
+    });
+
+    testUtils.testWithCluster('clusterNode.clusterLinks', async cluster => {
+        const links = await cluster.getSlotMaster(0).client.clusterLinks();
+        assert.ok(Array.isArray(links));
+        for (const link of links) {
+            assert.equal(typeof link.direction, 'string');
+            assert.equal(typeof link.node, 'string');
+            assert.equal(typeof link.createTime, 'number');
+            assert.equal(typeof link.events, 'string');
+            assert.equal(typeof link.sendBufferAllocated, 'number');
+            assert.equal(typeof link.sendBufferUsed, 'number');
+        }
+    }, GLOBAL.CLUSTERS.OPEN);
+});