add example component to AJAX FAQ

content/docs/faq-ajax.md

@@ -13,3 +13,48 @@ You can use an AJAX library you like with React. Some popular ones are [Axios](h
 ### Where in the component lifecycle should I make an AJAX call?
 
 You should populate data with AJAX calls in the [`componentDidMount`](https://reactjs.org/docs/react-component.html#mounting) lifecycle method. This is so you can use `setState` to update your component when the data is retrieved.
+
+### Example: Using AJAX results to set local state
+
+The component below demonstrates how to make an AJAX call in `componentDidMount` to populate local component state. 
+
+The example API returns a JSON object like this:
+
+```
+{
+  items: [
+    { id: 1, name: 'Apples', price: '$2' },
+    { id: 2, name: 'Peaches', price: '$5' }
+  ] 
+}
+```
+
+```jsx
+class MyComponent extends React.Component {
+  constructor(props) {
+    super(props)
+    this.state = {
+      isLoaded: false,
+      error: null,
+      items: [],
+    }
+  }
+  
+  componentDidMount() {
+    fetch('https://api.example.com/items')
+      .then(res => res.json())
+      .then(result => this.setState({items: result.items))
+      .catch(err => this.setState({ err: error }))
+  }
+  
+  render() {
+    const {error, items} = this.state
+    if (err) return <div>{error}</div>
+    return (
+      <ul>
+        { items.map(item => <li>{item.name} {item.price}</li> }
+      </ul>
+    )
+  }
+}
+```