Functional programming is one of the most interesting topic in today’s JavaScript community. Pure functions and immutable data structures make for code that’s fun to test and easy to reason about … but creating interesting programs from pure computation is neither fun nor easy. This is where Functional Reactive Programming comes in. By wrapping data in observable objects, applying transformations and explicitly assigning side effects, functional programs turn into practical programs. This workshop is a comprehensive introduction into Functional Reactive Programming with RxJS. It covers the basics of FRP and large parts of RxJS’s API as well as advanced topics like creating custom operators and using marble tests for unit testing. Much of the material covered in this workshop can be applied to other libraries and programming languages that implement Functional Reactive Programming.