RACObserve subscribeNext didn't execute when value of the observed item changed? - objective-c

Question

hello everybody I have an weird issue , I putted this code in my bind method :
[RACObserve(self.viewModel,contacts) subscribeNext:^(id x) {
[self.contactsTableView reloadData];
}];
but when the contacts in my viewModel changed , the subscribeNext didn't execute !! , I checked if the value changed by debugging and it changed normally !!
this is where the value is changed in my view Model (Simplified) :
I initilized it here :
- (instancetype)init {
self.contacts = [[NSMutableArray <Contact *> alloc]init];
}
and changed here
#pragma mark - load and filter methods
- (RACCommand *)loadContactsCommand {
ContactsNetworkManager *contactNetworkManager = [ContactsNetworkManager sharedManager];
return [[RACCommand alloc] initWithSignalBlock:^RACSignal *(id input) {
return [[contactNetworkManager getAllContactsSignal] map:^id(NSMutableArray<Contact *> * value) {
NSSortDescriptor *descriptor = [[NSSortDescriptor alloc] initWithKey:#"firstName" ascending:YES];
[value sortUsingDescriptors:[NSArray arrayWithObject:descriptor]];
[_contacts removeAllObjects];
[_contacts arrayByAddingObjectsFromArray:value];
return value;
}];
}];
}
#pragma mark - Actions
- (void)loadContacts {
[self.loadContactsCommand execute:nil];
}
#end

Answer 1

find it , actually the solution is too simple , I had to use self rather than on an independent reference to the NSMutableArray object like _ . In other words, it won't work if you do that , because the KVO established by RACObserve() is relative to the object you pass in as its first parameter (self, in this case), so only KVC-compliant mutations that pass through the observed object will trigger the observation notifications.