Bugfix/issue 27 invalid item access

lib/client.js

@@ -274,6 +274,9 @@ export class RealtimeClient extends RealtimeEventHandler {
 
     // Setup for application control flow
     const handler = (event, ...args) => {
+      if (!this.realtime.isConnected()) {
+        return { item: null, delta: null };
+      }
       const { item, delta } = this.conversation.processEvent(event, ...args);
       return { item, delta };
     };
@@ -329,6 +332,9 @@ export class RealtimeClient extends RealtimeEventHandler {
     // Handlers to update application state
     this.realtime.on('server.conversation.item.created', (event) => {
       const { item } = handlerWithDispatch(event);
+      if (!item) {
+        return;
+      }
       this.dispatch('conversation.item.appended', { item });
       if (item.status === 'completed') {
         this.dispatch('conversation.item.completed', { item });
@@ -352,6 +358,9 @@ export class RealtimeClient extends RealtimeEventHandler {
     );
     this.realtime.on('server.response.output_item.done', async (event) => {
       const { item } = handlerWithDispatch(event);
+      if (!item) {
+        return;
+      }
       if (item.status === 'completed') {
         this.dispatch('conversation.item.completed', { item });
       }

test/tests/client_disconnect.js

@@ -0,0 +1,33 @@
+import * as chai from 'chai';
+const expect = chai.expect;
+
+import { RealtimeClient } from '../../index.js';
+
+export async function run({ debug = false } = {}) {
+  describe('RealtimeClient (Node.js) - Disconnect', () => {
+
+    it('Should not throw an error if the client disconnects while receiving messages', async function() {
+        this.timeout(10000);
+        const client = new RealtimeClient({
+          apiKey: process.env.OPENAI_API_KEY,
+          debug,
+        });
+
+        client.realtime.on('server.response.audio.delta', () => {
+          client.disconnect();
+        });
+
+        await client.connect();
+        await client.waitForSessionCreated();
+
+        client.sendUserMessageContent([{ type: 'input_text', text: 'Hello' }]);
+
+        await client.waitForNextCompletedItem();
+
+
+        expect(client).to.exist;
+
+      });
+    });
+
+}