When using Ext JS, we need to change our mind and see everything as an object or class. We need to think carefully how we're going to organize the classes, as this will help us in the future chapters. Also you learned how to work with OOP with the class system in Ext JS.
You also learned about the loader system to import our classes dynamically, managing dependencies for us, and only loading what we need. At the end of this chapter, you learned about the DOM and how to perform a search in order to manipulate the nodes easily.
In the next chapter, you'll learn about the layout system, a powerful way to create and manage our layouts. Using and combining several types of layouts will help us to create unique interfaces.