Connecting to data services and APIs and handling asynchronous information is a common task in our everyday lives as developers. In this sense, Angular provides an unparalleled tool set to help its enthusiastic developers when it comes to consuming, digesting, and transforming all kinds of data fetched from data services.

There are so many possibilities that it would require an entire book to describe all that you can do to connect to APIs or to consume information from the filesystem asynchronously through HTTP. In this book, we will only scratch the surface, but the insights covered in this chapter about the HTTP API and its companion classes and tools will give you all that you need to connect your applications to HTTP services in no time, leaving all that you can do with them up to your creativity.

In this chapter, we will:

• Look at the different strategies for handling asynchronous data
• Introduce Observables and Observers
• Discuss functional reactive programming and RxJS
• Review the HTTP class and its API and learn some nice service patterns
• Learn about Firebase and how to connect it to your Angular app
• See all of the preceding points in action through actual code examples