Book Image

Reactive Programming in Kotlin

By : Rivu Chakraborty
Book Image

Reactive Programming in Kotlin

By: Rivu Chakraborty

Overview of this book

In today's app-driven era, when programs are asynchronous, and responsiveness is so vital, reactive programming can help you write code that's more reliable, easier to scale, and better-performing. Reactive programming is revolutionary. With this practical book, Kotlin developers will first learn how to view problems in the reactive way, and then build programs that leverage the best features of this exciting new programming paradigm. You will begin with the general concepts of Reactive programming and then gradually move on to working with asynchronous data streams. You will dive into advanced techniques such as manipulating time in data-flow, customizing operators and provider and how to use the concurrency model to control asynchronicity of code and process event handlers effectively. You will then be introduced to functional reactive programming and will learn to apply FRP in practical use cases in Kotlin. This book will also take you one step forward by introducing you to Spring 5 and Spring Boot 2 using Kotlin. By the end of the book, you will be able to build real-world applications with reactive user interfaces as well as you'll learn to implement reactive programming paradigms in Android.
Table of Contents (20 chapters)
Title Page
Credits
About the Author
About the Reviewers
www.PacktPub.com
Customer Feedback
Dedication
Preface

Combining producers (Observable/Flowable)


While developing applications, it's a common situation to combine data from multiple sources before using them. One such situation is when you are building some offline application following an offline-first approach, and you want to combine the resultant data you got from the HTTP call with the data from the local database.

Now, without wasting much time, let's take a look at the operators that can help us combine producers:

  • startWith()
  • merge(), mergeDelayError()
  • concat()
  • zip()
  • combineLatest()

Basically, there are a few mechanisms to combine producers (Observables/Flowables). They are as follows:

  • Merging producers
  • Concatenating producers
  • Ambiguous combination of producers
  • Zipping
  • Combine latest

We will discuss all the previously mentioned techniques to combine producers in this chapter. However, let's start with an operator that we are already aware of.

The startWith operator

We got introduced to the startWith operator in the previous chapter, but there's still...