Każdy programista powinien posiadać bogaty narzędziownik, który będzie pomagać mu w rozwiązywaniu wszelakich problemów, jakie napotyka na swojej drodze. Jednym z najlepszych narzędzi, jakie powinno się w nim znaleźć, jest zdobywające popularność programowanie funkcyjne. W czasie swojej prelekcji Krzysztof zaprezentował jak wykorzystać moc tego stylu programowania przy tworzeniu (często skomplikowanych) frontendowych rozwiązań oraz dlaczego warto go stosować. Przedstawił także problemy, które rozwiązane zostały po zastosowaniu kilku funkcyjnych trików oraz opowiedział o tym, jak na tych rozwiązaniach mogą skorzystać całe zespoły.

1. Functional Frontend
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2. LET’S START
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3. Functional programming has had a
recent renaissance that is due
largely to its utility in distributed
systems
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4. Functional programming:
PARADIGM
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5. Functional programming:
CODING STYLE
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6. Functional programming:
MINDSET
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7. Functional programming is a
natural fit for JavaScript
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8. #futuredevday / @kjendrzyca / aimforsimplicity.com

9. First-class functions, closures, and
simple lambda syntax
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10. #futuredevday / @kjendrzyca / aimforsimplicity.com

11. CONCEPTS
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12. LAMBDA CALCULUS
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13. Lambda calculus is a formal
system in mathematical logic for
expressing computation based on
function abstraction and application
using variable binding and
substitution. ~Wikipedia
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14. #futuredevday / @kjendrzyca / aimforsimplicity.com

15. PURE/STATELESS FUNCTIONS
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16. Pure Functions will always produce
the same output given the same
inputs
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17. All useful Pure Functions must
return something
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18. #futuredevday / @kjendrzyca / aimforsimplicity.com

19. #futuredevday / @kjendrzyca / aimforsimplicity.com

20. No side-effects
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21. #futuredevday / @kjendrzyca / aimforsimplicity.com

22. #futuredevday / @kjendrzyca / aimforsimplicity.com

23. #futuredevday / @kjendrzyca / aimforsimplicity.com

24. #futuredevday / @kjendrzyca / aimforsimplicity.com

25. Some parts of every program must
be impure
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26. Composition
const mult5AfterAdd10 = value => mult5(add10(value))
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27. HIGHER-ORDER FUNCTIONS
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28. Either take functions as
parameters, return functions or
both
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29. #futuredevday / @kjendrzyca / aimforsimplicity.com

30. Core of functional JS
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31. “INVARIABLE VARIABLES” /
IMMUTABILITY
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32. #futuredevday / @kjendrzyca / aimforsimplicity.com

33. #futuredevday / @kjendrzyca / aimforsimplicity.com

34. CLOSURES
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35. In JavaScript, a closure is created
whenever a function accesses a
variable defined outside the
immediate function scope.
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36. #futuredevday / @kjendrzyca / aimforsimplicity.com

37. Mechanism for containing state
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38. Data privacy in JavaScript using a
factory function
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39. #futuredevday / @kjendrzyca / aimforsimplicity.com

40. DATA MANIPULATION
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41. map()
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42. This method is for when you have
an array with one structure and
need to map it to another structure
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43. #futuredevday / @kjendrzyca / aimforsimplicity.com

44. #futuredevday / @kjendrzyca / aimforsimplicity.com

45. reduce()
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46. Returning a single value from an
array is fairly common in functional
programming, so much so that it
has a special name, “reduction"
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47. #futuredevday / @kjendrzyca / aimforsimplicity.com

48. #futuredevday / @kjendrzyca / aimforsimplicity.com

49. #futuredevday / @kjendrzyca / aimforsimplicity.com

50. filter()
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51. #futuredevday / @kjendrzyca / aimforsimplicity.com

52. #futuredevday / @kjendrzyca / aimforsimplicity.com

53. chaining
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54. LIBRARIES TO CONSIDER
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55. LODASH
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56. #futuredevday / @kjendrzyca / aimforsimplicity.com

57. RAMDA
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58. #futuredevday / @kjendrzyca / aimforsimplicity.com

59. UI
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60. #futuredevday / @kjendrzyca / aimforsimplicity.com

61. #futuredevday / @kjendrzyca / aimforsimplicity.com

62. #futuredevday / @kjendrzyca / aimforsimplicity.com
COMPOSITION

63. #futuredevday / @kjendrzyca / aimforsimplicity.com

64. #futuredevday / @kjendrzyca / aimforsimplicity.com

65. REACT
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66. #futuredevday / @kjendrzyca / aimforsimplicity.com

67. REDUX
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68. Action
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69. Reducer
A pure function that takes the
previous state, an action and
returns the new state
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70. #futuredevday / @kjendrzyca / aimforsimplicity.com

71. #futuredevday / @kjendrzyca / aimforsimplicity.com

72. #futuredevday / @kjendrzyca / aimforsimplicity.com

73. #futuredevday / @kjendrzyca / aimforsimplicity.com

74. Try ELM
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75. #futuredevday / @kjendrzyca / aimforsimplicity.com

76. How does it help me?
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77. Closures === data privacy
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78. Pure functions === Composability
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79. Clean data manipulation
No for loops with custom logic
inside - chained, higher order
functions instead
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80. Big part of the code base without
side effects
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81. Better abstraction levels
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82. The ability to move code around
freely between files, modules,
projects, and so on
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83. Increased predictability and
testability
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84. Easy to reason about UI
Thanks to React and Redux
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85. #futuredevday / @kjendrzyca / aimforsimplicity.com

86. Srouces:
https://www.smashingmagazine.com/2014/07/dont-be-scared-of-functional-programming/
https://medium.com/javascript-scene/the-two-pillars-of-javascript-pt-2-functional-programming-a63aa53a
41a4#.5193izn1p
https://drboolean.gitbooks.io/mostly-adequate-guide
https://medium.com/@cscalfani/so-you-want-to-be-a-functional-programmer-part-1-1f15e387e536#.9yie7
49gk
https://developer.mozilla.org/en/docs/Web/JavaScript/Closures
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