如何从订阅的RACSignal获取错误值？

Question

For example:

In one controller, implementation

func sendSuccessOrNot()->RACSignal {
// code here
}

In another controller, calling that signal

controller.sendSuccessOrNot().subscribeNext {

}

how to check in the above calling if sendSuccessOrNot is sending error or success value in ReactiveCocoa.

Answer 1

The syntax you use makes me think you're using Swift, in which case you shouldn't be using RACSignal, you should be converting your RACSignal to a SignalProducer with .toSignalProducer()

func sendSuccessOrNot() -> RACSignal {
    return RACSignal.createSignal { (subscriber) -> RACDisposable! in
        let test = true
        if (test) {
            subscriber.sendNext("Value")
            subscriber.sendCompleted()
        } else {
            subscriber.sendError(NSError(domain: "", code: 0, userInfo: nil))
        }
        return RACDisposable(block: {})
    }
}

controller.sendSuccessOrNot().toSignalProducer().on(next: { value in
    print("next: \(value)")
}, 
failed: { error in
    print("failed: \(error)")
}).start()

If you're still using RAC 2 then it'd be

controller.sendSuccessOrNot().subscribeNext({ value in
    print("next: \(value)")
}, error: { error in
    print("failed: \(error)")
})