StockItemMockService misnamed/App.default missing in App.jsx after step

**Describe the bug**
Through Inventory Micro App - Part 2. Instructions *Add a service component to get mock Stock Items*, you're asked to create a StockItemMockService class, along with configuring App.jsx and App.test.jsx to work with it.

following instructions includes a typo for App.jsx:

```js
class App extends Component {
constructor(props) {
super(props);
this.stockService = props.stockService || new MockStockService();
}
```
instead of new `StockItemMockService`

finally, following this configuration from the guide creates a `./src/index.js
Attempted import error: './App' does not contain a default export (imported as 'App').`

**To Reproduce**
Steps to reproduce the behavior:
1. Follow Inventory Micro App - Part 1, create a reactui template
2. during the service portion of the app, follow instructions
3. try to run npm start:dev

**Expected behavior**
I imagine the app should run normally with the service implemented?

**Screenshots**

**IBM Cloud**
Select the services and tools affected

- [ ] IBM Kubernetes Service Managed Service
- [ ] Red Hat OpenShift Managed Services
- [ ] Jenkins
- [ ] Tekton
- [ ] SonarQube
- [ ] Pact
- [ ] Artifactory
- [ ] IBM Image Registry

**Desktop (please complete the following information):**
- OS: OSX Catalina
- Browser Chrome

**Additional context**
Is adding export default App, the correct way to troubleshoot this? I'm unfamiliar with React