RAChelp.m

- (void)thing
{
  // So I have two signals…
  RACSignal *addedSignal = [[NSNotificationCenter defaultCenter] rac_addObserverForName:@"added" object:nil];
  RACSignal *removedSignal = [[NSNotificationCenter defaultCenter] rac_addObserverForName:@"removed" object:nil];
  
  // This doesn't get called until removedSignal gets it's first thingy.
  [[RACSignal combineLatest:@[addedSignal, removedSignal]] subscribeNext:^(id x) {
    // TODO could this binding be better?
    [self.data replaceObjectAtIndex:0 withObject:self.meteorClient.collections[@"posts"]];
    [self.collectionView reloadData];
  }];
  
  
  // addedSignal always gets called immediately so this works
  [[RACSignal combineLatest:@[addedSignal]] subscribeNext:^(id x) {
    // TODO could this binding be better?
    [self.data replaceObjectAtIndex:0 withObject:self.meteorClient.collections[@"posts"]];
    [self.collectionView reloadData];
  }];
  
  // so I can replace it with these two
  [addedSignal subscribeNext:^(id x) {
    [self.data replaceObjectAtIndex:0 withObject:self.meteorClient.collections[@"posts"]];
    [self.collectionView reloadData];
  }];
  [removedSignal subscribeNext:^(id x) {
    [self.data replaceObjectAtIndex:0 withObject:self.meteorClient.collections[@"posts"]];
    [self.collectionView reloadData];
  }];
  
  // but that sucks.
  
  // I know you can use
  RACAbleWithStart(…);
  
  // but I can't figure out how to get a NotificationCenter signal to broadcast an initial value.
  
  // or maybe I'm not looking for combineLatest at all? how do I get two signals to merge
  // even if one hasn't published anything yet?

}