Add connection status check example and documentation. (#2340)

* Adds example for transactions with arbitrary commands.

* Formatting.

* Adds isReady doc and example for isReady and isOpen.

* Improved example.

* Added isOpen explanation.

* Removed example from a different PR.

examples/check-connection-status.js

@@ -0,0 +1,28 @@
+// Check the connection status of the Redis client instance.
+import { createClient } from 'redis';
+
+const client = createClient();
+
+console.log('Before client.connect()...');
+
+// isOpen will return False here as the client's socket is not open yet.
+// isReady will return False here, client is not yet ready to use.
+console.log(`client.isOpen: ${client.isOpen}, client.isReady: ${client.isReady}`);
+
+// Begin connection process...
+const connectPromise = client.connect();
+
+console.log('After client.connect()...');
+
+// isOpen will return True here as the client's socket is open now.
+// isReady will return False here as the promise hasn't resolved yet.
+console.log(`client.isOpen: ${client.isOpen}, client.isReady: ${client.isReady}`);
+
+await connectPromise;
+console.log('Afer connectPromise has resolved...');
+
+// isOpen will return True here as the client's socket is open now.
+// isReady will return True here, client is ready to use.
+console.log(`client.isOpen: ${client.isOpen}, client.isReady: ${client.isReady}`);
+
+await client.quit();