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 model our objects and data. We have learned how to work with object-oriented programming with the new class system.
We also learned about the new loader system to import our classes dynamically, managing dependencies for us, and only loading what we need. At the end of this chapter we learned about the DOM and how to perform a search in order to manipulate the nodes easily.
In the next chapter we'll learn about the layout system, a powerful way to create and manage our layouts. There are several types of layouts that we can use and combine to create unique interfaces.