Interacting with RESTful APIs is a very common task we need to do when building an app, and it always results in us having to write asynchronous code. So, to begin with in this chapter, we'll have a detailed look at asynchronous code in general.

There are many libraries that we can use to help us interact with REST APIs. In this chapter, we'll look at both a native browser function and a popular open source library for interacting with REST APIs. We'll discover the additional features that the open source library has over the native function. We will also look at how we can interact with a REST API in both React class and function-based components. 

In this chapter, we'll learn the following topics:

• Writing asynchronous code
• Using fetch
• Using axios with class components
• Using axios with function components