chore: added failover example (#181)

Co-authored-by: Karl Lingiah <karl@superchilled.co.uk>

Author: manchuck

messages/send-message-with-failover.js

@@ -0,0 +1,47 @@
+require('dotenv').config({ path: __dirname + '/../../.env' });
+
+const VONAGE_APPLICATION_ID = process.env.VONAGE_APPLICATION_ID;
+const VONAGE_PRIVATE_KEY = process.env.VONAGE_PRIVATE_KEY;
+const MESSAGES_TO_NUMBER = process.env.MESSAGES_TO_NUMBER;
+const RCS_SENDER_ID = process.env.RCS_SENDER_ID;
+const SMS_SENDER_ID = process.env.SMS_SENDER_ID;
+const MESSAGES_API_URL = process.env.MESSAGES_API_URL;
+
+const { Vonage } = require('@vonage/server-sdk');
+const { Channels, MessageType } = require('@vonage/messages');
+
+/**
+ * It is best to send messages using JWT instead of basic auth. If you leave out
+ * apiKey and apiSecret, the messages SDK will send requests using JWT tokens
+ *
+ * @link https://developer.vonage.com/en/messages/technical-details#authentication
+ */
+const vonage = new Vonage(
+  {
+    applicationId: VONAGE_APPLICATION_ID,
+    privateKey: VONAGE_PRIVATE_KEY,
+  },
+  {
+    ...(MESSAGES_API_URL ? { apiHost: MESSAGES_API_URL } : {}),
+  },
+);
+
+vonage.messages.send({
+  to: MESSAGES_TO_NUMBER,
+  from: RCS_SENDER_ID,
+  channel: Channels.RCS,
+  messageType: MessageType.TEXT,
+  text: 'This is an RCS text message sent via the Vonage Messages API.',
+  failover: [
+    {
+      to: MESSAGES_TO_NUMBER,
+      from: SMS_SENDER_ID,
+      channel: Channels.SMS,
+      messageType: MessageType.TEXT,
+      text: 'This is an SMS sent using the Vonage Messages API.',
+
+    }
+  ]
+})
+  .then(({ messageUUID }) => console.log(messageUUID))
+  .catch((error) => console.error(error));