Enhanced Youtube # 6 - Show selected video at video details

app.js

// at app.js -- write a call back to update selectedVideo & provide that as props at VideoList
onVideoSelect={selectedVideo => this.setState({selectedVideo})}

// at video.list.js -- extract the callback from props and send that to VideoListItem
const onVideoSelect = props.onVideoSelect;
const videoList = videos.map( v => <VideoListItem onVideoSelect={onVideoSelect} key={v.etag} video={v} />);
                             
// at video.list.item.js -- call the call back
const VideoListItem = ({video, onVideoSelect})
<li className="list-group-item" onClick={() => onVideoSelect(video)}>