If you ever checked the annotated source code (http://backbonejs.org/docs/backbone.html) of Backbone, you might have found that the library footprint is very small (the production file is only 6.4 KB at v1.1.0). Its sole purpose is to improve the structure and maintainability of your code with the least complexity. So, once you start using Backbone, you will find that in every step of the development, you need to write custom widgets and plugins. In this chapter, we learned the basics of Backbone.js and the utility of using Underscore.js with Backbone.js. We also saw how developing reusable components and custom pugins can reduce boilerplate from our code. In the end, we understood the concept of JavaScript plugins and discussed different approaches for defining mixins. We are going to use all these concepts several times in the following chapters.

In the next chapter, we will discuss different problems associated with Backbone views and possible solutions to them. We will also see how custom-view plugins or mixins can solve most of the problems.