github/ReactiveCocoa — pull request #154 by thenikso (2012-11-30 00:37:08+00:00)
Title: Add `-collect` method to RACSignal

Spawned from #148, `-collect` aims to provide a push-based semantic for the `-toArray` functionality.

An example use case is updating an `NSArray *` property from a signal that sends a `next` for every value to add to the destination array.
```
@property (copy) NSArray *myFileURLs;
...
RACSignal *fileURLsInDirectorySignal = *A signal that send `next` for every URL in a directory*;

[[fileURLsInDirectorySignal collect] toProperty:@keypath(self.myFileURLs) onObject:self];
```