In this chapter, you learned how to enable routing, and you also quickly overviewed responsible design and touch support for Ext JS applications. You learned about the importance of knowing how to debug an Ext JS application and about some tools that can help us with this task. You also learned that performance is really important and that we can do a lot more to improve the performance of our Ext JS application with the help of some free tools. We also listed where to find great plugins, extensions, and new components that we can use in our projects.

In the next chapter, we will customize the theme for our application, and we will perform the production build.