With applications written in JavaScript becoming more and more complex, the need for stronger application design has increased. Browser applications are growing, and the business reliance on them grows as well. Due to this, what used to be a domain of backend development starts to become important in frontend development. For a long time now, people have been evolving the way backend applications can be modeled for flexibility, so they can grow with the business, and now browser applications need to do the same. There is a lot to learn from the approaches that have been developed over the years, and even though some are not directly transferable to JavaScript, or might not even be needed, the general ideas port over very well. I hope I was able to present some of these ideas throughout the book.

On the other hand, with the rise and adoption of Node.js as a platform for application development, JavaScript has moved into the backend as well, and the same challenges that needed solving...