FRP is a reactive programming paradigm that uses functional programming building blocks. It models UI components as streams/observables and uses pure functions as operators to process and propagate change between these streams. State is represented using subjects that emit new stream values in response to events rather than mutable variables. Higher order operators like map and switchMap allow streams of streams to be processed, with switchMap useful for modeling asynchronous operations like HTTP requests. The learning curve for FRP takes effort but pays off in declarative, reactive programs.

1. How do you do
that in FRP?
@_bondit_Netta Bondy

4. What is FRP?
Functional reactive programming (FRP) is a
programming paradigm for reactive programming
using the building blocks of functional programming
wikipedia.org

5. Reactive Programming
reactive programming is a declarative programming
paradigm concerned with data streams and the
propagation of change
wikipedia.org

6. Streams = Observables

7. 1
Observable / stream
UI component
UI component
UI component
1
1
1

8. Functional Programming
functional programming is a programming paradigm
that treats computation as the evaluation of
mathematical functions and avoids changing-state
and mutable data
wikipedia.org

9. Pure Functions =
Operators

10. 16
random
int
UI component
^2 filter odd
Observable
Operators

11. State (??)

12. ButtonSelected ButtonButtonSelected Button

13. isNotSelected
click
isSelected
click
isNotSelected
isNotSelected isSelected isNotSelected

14. State = Subjects

15. initalFilters
click
newFilters
click
newFilters
initialFilters newFilters newFilters

16. State = Subjects

17. Streams of Streams:
Higher Order Operators

18. Map operator
stream new stream.map()

19. Higher order mapping operator
mergeMap

20. switchMap
switchMap

21. switchMap(click → request → response)
click clickclickclick click
response responseresponse

22. switchMap(click → request → response)
+blue -gray+gray
response response

23. The FRP Learning Curve
Pays Off

24. Thank You!
1st example
2nd example
@_bondit_