ReactiveCocoa for a Better World

Cocoa apps spend a lot of time waiting and then reacting. We wait for the user to do something in the UI. Wait for a network call to respond. Wait for an asynchronous operation to complete. Wait for some dependent value to change. And then they react. But all those things—all that waiting and reacting—is usually handled in many disparate ways. That makes it hard for us to reason about them collectively, chain them, or compose them in any uniform, high-level way. We can do better. ReactiveCocoa is a framework for composing and transforming sequences of values. We'll talk about how we can use ReacticeCocoa to write better, more succinct and more expressive code.

Transcript

1. (Bonjour.)
2. Josh Abernathy @joshaber
5. Story time.
9. Reactive Extensions (Rx)
10. Erik Meijer
11. ReactiveCocoa (RAC)
12. for a ReactiveCocoa Better World
13. PHILOSOPHY
14. Idea > Code
15. Not “easy”
16. But it’s good.
17. “A framework for composing and transforming sequences of values.”
18. “A framework for composing and transforming sequences of values.” — Scumbag Josh
19. It’s like a series of tubes...
20. “A sequence of values over time.”
21. “A sequence of values over time.” — Me, just now
22. RACSubscribable
23. RACSubscribable
24. RACSubscribable
25. RACSubscriber
26. Subscription Iteration
27. That’s it!
28. ???
29. Async work
30. Network request
31. UI events
32. KVO
33. ???
34. KVO property = UI events = Network request = Async work = ??? = Subscribables
35. Shared Vocabulary
36. Shared Toolset
37. Composable
38. It’s all about The Operators
39. Compose Combine Transform
42. PHILOSOPHY
44. Expressive
45. Expressive (But dense.)
47. Code Locality
49. Less State
51. It’s all about The Operators
52. It’s all about The Operators (There are a lot of operators.)
53. -select: Hi to all HI ALL TO
54. -where: A B A A A
55. +merge:
56. -throttle:
57. -selectMany:
58. -selectMany:
59. -selectMany: “When I get a value, subscribe to the next subscribable.”
60. -selectMany: “When I get a value, subscribe to the next subscribable.”
61. -selectMany: Look, it’s about chaining ok?
63. -takeUntil:
64. -catch:
65. Errors? What errors?
66. -catch:
67. Where do subscribables Come from?
68. Hot vs. Cold
69. Honey badger don’t care Hot: Everyone gets the same thing
70. Honey badger most certainly does care Cold: Everyone’s separate
71. PHILOSOPHY
72. So Lazy.
73. Subscribing can have side effects
74. -retry:
75. -repeat:
76. Where do subscribables Come from? No seriously,
77. Cold: +createSubscribable:
80. Hot: Subjects
83. RACSubject
84. RACAsyncSubject RACSubject
85. RACAsyncSubject RACSubject RACReplaySubject
86. RACAsyncSubject RACSubject RACReplaySubject RACBehaviorSubject
88. -defer: “I’ll give you a subscribable when someone subscribes.” Hot to Cold
89. -publish/-multicast: “Funnel everything through one subscription.” Hot to Cold
90. PHILOSOPHY
91. Not “easy”
92. But it’s good.
93. github.com/github/ReactiveCocoa More Info: Reactive Extensions (Rx) @joshaber
94. (Fin.)