This chapter introduced you to the concept of a collection and how they can be compared to arrays. Lo-Dash treats collections as an abstract concept—all JavaScript arrays are collections, but not all collections are arrays. We were introduced to the concept of iterating over collections using the tools provided by Lo-Dash—a fundamental concept in applicative programming and will be touched upon frequently throughout this book.

Collections can be filtered and items can be fetched from the collection. Lo-Dash also gives you the tools needed to transform collections into other structures you need when implementing frontend UI components.

We've been given a taste of some common themes in Lo-Dash programming—like the idea that callback functions are central to almost everything, and the various shorthands that can save on coding effort, such as the pluck and where callbacks. Now it's time to look at how Lo-Dash works with objects, and the various functions at our disposal there, which will be covered in the next chapter.