Why you should care about Elm

Transcript

1. Why you should care about Elm . 0 @terezk_a
2. Who am I? 1 @terezk_a
3. 2 @terezk_a
4. Copenhagen, Denmark 3 @terezk_a
5. React.js → Elm 4 @terezk_a
6. Elm-plot 5 @terezk_a
7. Agenda Today’s developer experience ✨ How do we fix it? ☔ Elm to the rescue! 6 @terezk_a
8. Part I: Today’s developer experience 7 @terezk_a
9. @terezk_a 8
10. The promise 9 @terezk_a
11. Unfortunate circumstances 10 @terezk_a
12. Unfortunate circumstances Pressure from deadline Bad management Lack of team communication New on the team … Bad day 11 @terezk_a
13. I’ll fix it later 12 @terezk_a
14. Emotional consequence 13 @terezk_a
15. Part II: How do we fix it? ✨ 14 @terezk_a
16. Mutation of state is the work of the devil, don’t do it!!!!! (but like ok, if you really need to then whatever) adasdfgsdafgsafgdsafhdvfsga dghf safgd sagfdh sfgad gfsad gfs fghas fgas fgsad fghas fgha desafg arjegrjhrhsgvrehskjggevhlragjvhrkagd jkhrg bdjhvgcnrldajvrjhfdgv sdjhxfgchjvgjkbscgjhkgncjhfdksgvjhkdfg nxghfdskcnjfhdcgnkjhgsdcngkjfhgsjfhgjhfshjkfgnkjsgkfhjdgsckhjfnsjfkgskjdfhjkcsnjkdfhsgcnjksgc njsjkgghjkfcnsjhkdncghjdfnscjhkgnjkfhdgskjhcnfsjhgcnfghjgnfhjkdsgcnfkjnsgshjkfdgncjhdfskncgh jfdckgnfksjhdcgnkjhfsncjhgfnsjhkcnhjsg Type checking, but only like sometimes, great ¯\_(ツ)_/¯ hlp pls wat 15 Unidirectional data flow, yay more stuff @terezk_a
17. Does it fix it? Theoretically, yes 16 @terezk_a
18. Let start over 17 @terezk_a
19. What are we even trying to do? State 18 @terezk_a
20. What are we even trying to do? State View 19 @terezk_a
21. What are we even trying to do? State View Event 20 @terezk_a
22. What are we even trying to do? State View Event Event => State 21 @terezk_a
23. What are we even trying to do? State View Event Event => State Timer, mouse position etc. Event 22 @terezk_a
24. What are we even trying to do? State View Event Event => State HTTP request, other async stuff Event Timer, mouse position etc. Event 23 @terezk_a
25. The Elm architecture Model View Message Update Commands Message Subscriptions Message 24 @terezk_a
26. You can do that in JavaScript? 25 @terezk_a
27. You can do anything in JavaScript View Message Update Commands Message Subscriptions Message 26 @terezk_a Model “I’ll fix it later” Mutated, unclean
28. Part III: Elm to the rescue! ☔ 27 @terezk_a
29. Constrains 28 @terezk_a
30. Only pure functions 29 @terezk_a
31. Pure and impure functions // Impure function function addOne(x) { x++; fireMissiles(); } // Pure function function addOne(x) { return x + 1; } 30 @terezk_a
32. Pure functions and immutability // JavaScript ✨ // (anything goes) var x = { foo: ”bar” } var y = f(x) -- Elm -- (only pure functions) x = { foo = “bar” } y = f x 31 x is always unchanged What is x? ¯\_(ツ)_/¯ @terezk_a
33. Static type system 32 @terezk_a
34. Static types and type inference -- With function signature horizontalGrid : List GridAttr -> PlotElement msg horizontalGrid attrs = Grid (List.foldr (<|) defaultGridConfig attrs) -- Without function signature horizontalGrid attrs = Grid (List.foldr (<|) defaultGridConfig attrs) 33 @terezk_a
35. No run time errors! 34 @terezk_a
36. No run time errors!!!!!!!!!! 35 @terezk_a
37. No run time errors???? dostoevsky = { firstName = "Fyodor” , lastName = "Dostoevsky” } greet person = "Hello " ++ person.firstname main = text (greet dostoevsky) 36 The compiler The program @terezk_a
38. Ok, but really??? 37 @terezk_a
39. Enforced semantic versioning 38 @terezk_a
40. Improved performance 39 @terezk_a
41. Time traveling debugger! ⏳ 40 @terezk_a
42. Tailored syntax 41 @terezk_a
43. Constrains Rules • Only pure functions • Static type system • Opinionated on architecture Benefits • No run time errors! • Enforced semantic versioning • Improved performance • ⏳ Time traveling debugger! 42 @terezk_a
44. The eco-system @terezk_a 43
45. JavaScript interop 44 @terezk_a
46. Gradual implementation 45 @terezk_a
47. Helpful community (#beginners!) 46 @terezk_a
48. That’s why you should care about Elm 47 @terezk_a
49. Q & A 48 @terezk_a
50. Contact Tereza Sokol terezasokol@gmail.com terezk_a terezka 49 @terezk_a