In Swift, how do I guard against calling storyboard.instantiateViewControllerWithIdentifier on an identifier that's not valid?
Most solutions I have seen on SO uses try...catch in Objective-C, but the solution does not work in Swift because instantiateViewControllerWithIdentifier does not throw.
I believe it's a bug in the current API (iOS 9 as of today) for the Swift version. Either storyboard.instantiateViewControllerWithIdentifier should return UIViewController? or it should be able to throw exception. The Objective-C version throws exception which can be dealt with try-catch clause.
