Best way to remove force unwrapping

Question

var recorder : Recorder? = nil

func startAudioRecording() {
    if recorder == nil {
        recorder = Recorder()
    }
    if !recorder!.isRunning() {
        recorder?.startRecording({ [weak self] audioData in
            self?.remoteInterface?.sendVoice(audioData.0)
        }, withCompletionBlock: { (_) in })
    }
}

func stopAudioRecording(_ keyCommand: String!){
    if let _ = recorder {
        if(recorder?.isRunning())! {
            recorder?.stopRecording(completionBlock: { (isFinished: Bool) in
                DispatchQueue.global().asyncAfter(deadline: DispatchTime.now() + Double(Int64(1 * NSEC_PER_MSEC)) / Double(NSEC_PER_SEC), execute: { [unowned self] in
                    self.remoteInterface?.sendTouchUp(keyCommand)
                    self.audioRecorder = nil
                })
            })
        }
    }
}

How we can remove the force unwrap?

Milan Nosáľ · Accepted Answer · 2018-01-22T10:06:40.887

First one you can deal with using if let (or alternatively guard let):

if let recorder = recorder {
    // here it is unwrapped
} else {
    // handle nil case
}

In the second one I would use default value:

if (recorder?.isRunning() ?? false) {
    // ...
}

However, I see that you are already using if let in the second case, so you don't need that. So I think the best it would be with if let in both case, so maybe something like this:

var recorder : Recorder? = nil

func startAudioRecording(){
    if recorder == nil {
        recorder = Recorder()
    }
    if let recorder = recorder,
        !recorder.isRunning() {

        recorder.startRecording({ [weak self] audioData in
            self?.remoteInterface?.sendVoice(audioData.0)
        }, withCompletionBlock: { (_) in })
    }
}

func stopAudioRecording(_ keyCommand: String!){
    if let recorder = recorder,
        recorder.isRunning() {

        recorder.stopRecording(completionBlock: { (isFinished: Bool) in
            DispatchQueue.global().asyncAfter(deadline: DispatchTime.now() + Double(Int64(1 * NSEC_PER_MSEC)) / Double(NSEC_PER_SEC), execute: { [unowned self] in
                self.remoteInterface?.sendTouchUp(keyCommand)
                self.audioRecorder = nil
            })
        })
    }
}

Or, as @Fogmaster noted, using guard in the second method might look a bit nicer:

func stopAudioRecording(_ keyCommand: String!){
    guard let recorder = recorder,
        recorder.isRunning() else {
        return
    }

    recorder.stopRecording(completionBlock: { (isFinished: Bool) in
        DispatchQueue.global().asyncAfter(deadline: DispatchTime.now() + Double(Int64(1 * NSEC_PER_MSEC)) / Double(NSEC_PER_SEC), execute: { [unowned self] in
            self.remoteInterface?.sendTouchUp(keyCommand)
            self.audioRecorder = nil
        })
    })
}

I would change the second function to use `guard` in stead of `if`. Helps reduce indentation and looks nicer. — Fogmeister, Jan 22 '18 at 10:03

score 1 · Answer 2 · answered Jan 22 '18 at 11:30

1

You could just make recorder lazy instead.

var recorder: Recorder = {
    return Recorder()
}()

answered Jan 22 '18 at 11:30

Samah

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Best way to remove force unwrapping

2 Answers2