Real World ReactiveCocoa ❤️

Transcript

1. ReactiveCocoa @RuiAAPeres Real World
2. 101 Signals
3. [RACObserve(self, usernameTextField) subscribeNext:^(NSString *newName) { NSLog(@"%@", newName); }]; Subscribers
4. Higher Order functions [[RACObserve(self, usernameTextField) filter:^(NSString *newName) { return [newName hasPrefix:@"j"]; }] subscribeNext:^(NSString *newName) { NSLog(@"%@", newName); }];
5. Bind + Derivation RAC(self, loginButton.enabled) = [RACSignal combineLatest: combinedSignals reduce:^(NSString *p, NSString *u) { return @(p.length > 0 && u.length > 0); }]; NSArray *combinedSignals = @[RACObserve(self, passwordTextField), RACObserve(self, usernameTextField)];
6. Composition [[[loginUserSignal flattenMap:^(User *user) { // Return a signal that loads cached messages for the user. return [client loadCachedMessagesForUser:user]; }] flattenMap:^(NSArray *messages) { // Return a signal that fetches any remaining messages. return [client fetchMessagesAfterMessage:messages.lastObject]; }] subscribeNext:^(NSArray *newMessages) { NSLog(@"New messages: %@", newMessages); } completed:^{ NSLog(@"Fetched all messages."); }];
7. “The power of these abstractions are very hard to convey to someone who has never had the privilege of learning them” Bartosz Milewski
9. ViewModel DataSource Storage
10. ViewModel
11. @interface RPNotificationsViewModel : NSObject @property(nonatomic,strong,readonly)RACCommand *notificationsCommand; @property(nonatomic,strong,readonly)RACSignal *errorMessageSignal; @property(nonatomic,strong,readonly)RACSignal *notificationsSignal; @end
12. DataSource
13. @interface RPNotificationsDataSource : NSObject @property(nonatomic,strong,readonly)RACSignal *dataSourceChanged; - (instancetype)initWithNotificationsSignal:(RACSignal *)signal; - (NSString *)titleForSection:(NSUInteger)index; @end
14. self.dataSourceChanged = [signal map:^id(NSArray *notifications) { NSArray *normalizedNotifications = // special sauce return normalizedNotifications; }];
15. @[OCTNotification1, OCTNotification2, OCTNotification3…]; Map from an Array to a NSOrderedSet fold @[“RuiPeres/Octify, iOS-Goodies/iOS-Goodies, ReactiveCocoa/ReactiveCocoa];
16. @“ReactiveCocoa/ReactiveCocoa” @“RuiAAPeres/Octify” @“iOS-Goodies/iOS-Goodies” [[signal map:^id(NSArray *notifications) { }]; @property(nonatomic,strong)NSOrderedSet *sections; return [NSOrderedSet orderedSetWithArray: ]; RAC(self,sections) = [notifications.rac_sequence foldLeftWithStart:[NSMutableOrderedSet orderedSet] reduce:^id(NSMutableOrderedSet *accumulator, OCTResponse *response) { OCTNotification *notification = response.parsedResult; [accumulator addObject:[notification ownerAndLogin]]; return accumulator; }].array
17. Storage
18. @interface RPNotificationsStorage : NSObject + (RACSignal *)storeNotifications:(RACSignal *)signal; + (RACSignal *)storedNotifications; @end
19. + (RACSignal *)storeNotifications:(RACSignal *)signal { return [signal doNext:^(NSArray *notifications) { // Store the notifications }]; }
20. + (RACSignal *)storedNotifications { return [RACSignal createSignal: ^RACDisposable *(id<RACSubscriber> subscriber) { NSError *error = // if something fails NSArray *notifications = // get notifications if (error) { [subscriber sendError:[NSError storedError]]; } else { [subscriber sendNext:notifications]; [subscriber sendCompleted]; } return nil; }]; }
21. The okay way
22. VM subscribed by VC DS UI ST
23. [self.notificationsViewModel.notificationsSignal subscribeNext:^(NSArray *notifications){ // 1. Store the notifications // 2. Update the Data Source // 3. Update the UI }];
24. “We can do better”
25. VM DS Observed + Bind Network -> DataSource
26. notifications = self.notificationsViewModel.notificationsSignal; dataSource = [[RPNotificationsDataSource alloc] initWithNotificationsSignal:notifications];
27. VM ST injected side effect DS Observed + Bind Network + Storage -> DataSource
28. notifications = self.notificationsViewModel.notificationsSignal; persistence = [RPNotificationsPersistence storeNotifications:notifications]; dataSource = [[RPNotificationsDataSource alloc] initWithNotificationsSignal:persistence];
29. ST DS Observed + Bind Storage -> DataSource
30. persistence = [RPNotificationsPersistence storedNotifications]; dataSource = [[RPNotificationsDataSource alloc] initWithNotificationsSignal:persistence];
31. DS UI Observed + Bind Observed + Bind UI
32. RAC(self,nyanCat.hidden) = [self.dataSource.dataSourceChanged map:^id(NSArray *notifications) { return [notifications count] == 0?@YES:@NO; }];
33. RAC([UIApplication sharedApplication],applicationIconBadgeNumber) = [[self.dataSource.dataSourceChanged filter:^BOOL(id value) { return [RPPreferences preference:RPBadgeCountPreference]; }] map:^id(NSArray *notifications) { return @([notifications count]); }];
34. VM ST side effect DS Observed + Bind UI Observed + Bind Observed + Bind UI
36. RACSequence *handlers = @[ @"twitter://user?screen_name=%@", @"tweetbot://%@/user_profile/%@", @"twitterrific:///profile?screen_name=%@", @“https://twitter.com/%@"].rac_sequence; return [[[[handlers map:^id(NSString *value) { return [NSString stringWithFormat:value,screenName,screenName]; }] map:^id(NSString *value) { return [NSURL URLWithString:value]; }] filter:^BOOL(NSURL *value) { return [[UIApplication sharedApplication] canOpenURL:value]; }] head];
37. Final thoughts
38. Thanks! @RuiAAPeres