Upgrade to Pro
— share decks privately, control downloads, hide ads and more …
Speaker Deck
Features
Speaker Deck
PRO
Sign in
Sign up for free
Search
Search
ReactiveCocoa
Search
Robert Böhnke
May 02, 2013
Programming
19
2.7k
ReactiveCocoa
My talk for UIKonf 2013 about ReactiveCocoa and how to get rid of state
Robert Böhnke
May 02, 2013
Tweet
Share
More Decks by Robert Böhnke
See All by Robert Böhnke
Brooklyn iOS Developer Meetup February 2014
robb
8
3.1k
Cocoa Kucha Berlin 2013
robb
2
2.1k
ReactiveCocoa NSSpain
robb
18
2.4k
Underscore.m + Asterism
robb
4
1.2k
Super Mario Masterclass
robb
2
320
Tetris Masterclass
robb
0
530
Other Decks in Programming
See All in Programming
Nuances on Kubernetes - RubyConf Taiwan 2025
envek
0
180
新しいモバイルアプリ勉強会(仮)について
uetyo
1
260
フロントエンドのmonorepo化と責務分離のリアーキテクト
kajitack
2
120
AHC051解法紹介
eijirou
0
600
エンジニアのための”最低限いい感じ”デザイン入門
shunshobon
0
120
DataformでPythonする / dataform-de-python
snhryt
0
180
Comparing decimals in Swift Testing
417_72ki
0
170
LLMOpsのパフォーマンスを支える技術と現場で実践した改善
po3rin
8
960
AIに安心して任せるためにTypeScriptで一意な型を作ろう
arfes0e2b3c
0
380
AIレビュアーをスケールさせるには / Scaling AI Reviewers
technuma
2
200
AIエージェント開発、DevOps and LLMOps
ymd65536
1
270
kiroでゲームを作ってみた
iriikeita
0
180
Featured
See All Featured
The Success of Rails: Ensuring Growth for the Next 100 Years
eileencodes
46
7.6k
The World Runs on Bad Software
bkeepers
PRO
70
11k
Bash Introduction
62gerente
614
210k
Typedesign – Prime Four
hannesfritz
42
2.8k
For a Future-Friendly Web
brad_frost
179
9.9k
Responsive Adventures: Dirty Tricks From The Dark Corners of Front-End
smashingmag
251
21k
Testing 201, or: Great Expectations
jmmastey
45
7.6k
Docker and Python
trallard
45
3.5k
Fireside Chat
paigeccino
39
3.6k
A Modern Web Designer's Workflow
chriscoyier
695
190k
Designing Dashboards & Data Visualisations in Web Apps
destraynor
231
53k
Distributed Sagas: A Protocol for Coordinating Microservices
caitiem20
333
22k
Transcript
ReactiveCocoa OR: How I stopped worrying about state and love
FRP
✉ robb
[email protected]
tmp ceterum_censeo
Let’s talk about State
evil √
Have you tried turning it off and on again?
Have you tried turning it off and on again? Have
you tried turning it off and on again?
state
@property (readwrite, …) BOOL quacksLikeADuck; @property (readwrite, …) BOOL walksLikeADuck;
@property (readonly, …) BOOL probablyADuck;
+ (NSSet *)keyPathsForValuesAffectingProbablyADuck { return [NSSet setWithObjects:@”walksLikeADuck”, @”quacksLikeADuck”, nil]; }
- (BOOL)isProbablyADuck { return _quacksLikeADuck && _walksLikeADuck; }
ReactiveCocoa
RAC(self.probablyADuck) = [RACSignal combineLatest:@[ RACAbleWithStart(self.walksLikeADuck), RACAbleWithStart(self.quacksLikeADuck) ] reduce:^(NSNumber *walks, NSNumber
*quacks) { return @(walks.boolValue && quaks.boolValue); }];
None
[self.usernameField addTarget:self action:@selector(textFieldDidUpdate:) forControlEvents:UIControlEventEditingChanged]; [self.emailField addTarget:self action:@selector(textFieldDidUpdate:) forControlEvents:UIControlEventEditingChanged]; - (void)textFieldDidUpdate:(UITextField
*)textField { BOOL validUsername = self.usernameField.text.length > 0; BOOL validEmail = [self.emailField.text uik_isEmail]; self.signupButton.enabled = validEmail && validUsername; }
because programming
[self.usernameField addTarget:self action:@selector(textFieldDidUpdate:) forControlEvents:UIControlEventEditingChanged]; [self.emailField addTarget:self action:@selector(textFieldDidUpdate:) forControlEvents:UIControlEventEditingChanged]; - (void)textFieldDidUpdate:(UITextField
*)textField { BOOL validUsername = self.usernameField.text.length > 0; BOOL validEmail = [self.emailField.text uik_isEmail]; self.signupButton.enabled = validEmail && validUsername; }
RAC(self.signupButton.enabled) = [RACSignal combineLatest:@[ self.usernameField.rac_textSignal, self.emailField.rac_textSignal ] reduce:^(NSString *username, NSString
*email) { BOOL validUsername = username.length > 0; BOOL validEmail = [email uik_isEmail]; return @(validUsername && validEmail); }];
FRP
None
None
ReactiveCocoa
@YES @NO @YES RACSignal
<UIControlEventEditingChanged> RACSignal
{“json_string”: “ohai”} RACSignal
RACSignal - (void)sendNext:(id)value; - (void)sendCompleted; - (void)sendError:(NSError *)error;
so, what?
map, reduce, filter
Let’s talk about Asynchrony
None
Blocks are awesome
void (^cb)(id operation, id result); void (^cb)(id operation, NSError *error);
void (^cb)(id result, NSError *error); void (^cb)(NSError *error, id result);
[client logIn:^{ [client loadMeUser:^(UIKUser *user) { [client loadNewslettersForUser:user success:^(NSArray *result)
NSLog(@"Your newsletters: %@", array); } failure:^(NSError *error) { // … }]; } failure:^(NSError *error) { // … }]; } failure:^(NSError *error) { // … }];
RACSignal
- (RACSignal *)logIn; - (RACSignal *)loadMeUser; - (RACSignal *)loadNewslettersForUser:(…)user;
[[[[client logIn] sequenceNext:^{ return [client loadMeUser]; }] flattenMap:^(UIKUser *user) {
return [client loadNewslettersForUser:user]; }] subscribeNext:^(NSArray *newsletters) { NSLog(@"Your newsletters: %@", newsletters); } error:^(NSError *error) { // … }];
None
- (RACSignal *)validateEmail:(NSString *)email;
RACSignal *validEmail = [[self.emailField.rac_textSignal map:^(NSString *email) { return [[client validateEmail:email]
startWith:@NO]; }] switchToLatest]; RACSignal *validForm = [RACSignal combineLatest:@[ validUsername, validEmail ] reduce:^(NSNumber *a, NSNumber *b) { return @(a.boolValue && b.boolValue); }]; RAC(self.signupButton.enabled) = validForm;
None
where's the catch?
•conceptual overhead •debugging can get tricky (logAll is your friend)
•forces you to think
should I use it?
Probably!
state
None