Accessing the Developer tools in my browser allows me to see the Domino has been built and also see the references to the bundle file a Webpack is created to render my app. These are shown in the script tux here. I can also get access to the files that are being used to create those bundles. I can do this by switching to the Sources tab and clicking through the folder structure. 

You can see here that I can see the App.js file and I could set breakpoints and watches, and then reload the application and debug it as I would do a normal JavaScript application. If I switched to the Console tab, you can see that I'm being told that there is a development tool available. If I follow the link here, it takes me to the React page, about the development tools. 

And as I'm using Chrome it gives me a link to the Chrome web store. I can add this to Chrome and then go back to my developer tools. These won't show until I close the tools down and reopen them. Although you can see that there's an icon appeared in the top right-hand corner next to the address bar. 

This time, you can see that I've got now a Components tab and a Profiler tab. We'll go into these into more detail later but this just lets me access the actual react components that are being rendered as part of my application, rather than the raw JavaScript. It also lets me access, things like seeing the matching DOM element. 

So clicking on it, opens up the elements and shows me exactly where the app component is rendered in my DOM. I can also ask it to output my components to the Console. If I click on this button here and then go to the Console and then expand this, it allows me to access some of the properties that are attached to my app components. The final button takes me to the part of the files that actually create that component. And as you can see, this is same as the App.js file that I showed earlier in this video.