Functional Programming

Functional Programming concept (in JavaScript). Internal share in RingCentral.

Transcript

1. Functional Programming
2. Outline • Why • What • How • Real world use cases
3. Outline • Why (1 mins) • What (20 mins) • How (10 mins) • Real world use cases (? mins)
4. Why • When I was young.
7. FP
9. What • Pure function • Function composition • Curry • Partial application • Monads & Functor • Immutability
10. Pure function • The function always evaluates the same result value given the same argument value(s). • Evaluation of the result does not cause any semantically observable side effect or output
11. Pure function • The function always evaluates the same result value given the same argument value(s). • Evaluation of the result does not cause any semantically observable side effect or output. • Function must return something.
12. Function composition • Higher-order function • Decorator pattern • Factory pattern • Strategy pattern
13. Curry
14. Curry
15. Partial application • Dependency injection • bind
16. Monads & Functor • Why: Chaining continuation • What: Container • How:
17. Monads & Functor • Example: Options
18. Monads & Functor • Example: Array
19. Monads & Functor • Example: Promise
20. Monad & Functor • "Once you understand monads, you start seeing them everywhere” - Eric Kidd
21. Monad & Functor
22. Monad & Functor
24. Monad & Functor • http://chrisdone.com/posts/monads-are-burritos
25. Immutability • Value, not place • “Can you give me the log for this error?”
26. How • Function as things • Composition everything • Types, not Class
27. How • Totality • Static type for modeling • Parameterise all the things
28. Real World • React / Redux • Elm • Haskell • Lisp
29. Real World • React / Redux • Elm • Haskell • Lisp
30. React / Redux • React • Redux
31. Elm
32. Haskell
33. Reference