Talking about Filtering Operators in RxSwift.

Discussing Ignore operators, Skip operators, Take operators, and Distinct operators.

This book by Ray Wenderlich acts as a complete guide toward learning and mastering reactive programming and asynchronous programming. This is currently using Swift 5.1 and iOS 13.

Links:

Step Into Swift: https://www.stepintoswift.com/
https://www.raywenderlich.com/books/rxswift-reactive-programming-with-swift
https://rxmarbles.com/