Web Development with ReasonML

Chapter 5Using Collections

In this chapter, we’ll investigate three ways to handle multiple, related pieces of data: tuples, lists, and arrays:

• Tuples let you collect items with different data types. They usually hold only a few items.

• Lists have elements that are all of the same data type, and are meant to be traversed from beginning to end.

• Array elements also must be of the same data type, but they allow efficient random access to the elements.

For lists and arrays, we’ll learn about the Belt.List and Belt.Array modules, which contain a large number of functions that make it easier to manipulate these collections. We’ll also start using three very important higher-order functions: map, reduce, and keep. Combining these functions lets you ...