Clear UserDefaults

To clear all UserDefaults from an app, maybe try this:

if let appDomain = Bundle.main.bundleIdentifier {
    UserDefaults.standard.removePersistentDomain(forName: appDomain)
}

Thanks to Sourabh Sharma for this idea.

Or maybe just:

UserDefaults.standard.removePersistentDomain(forName: Bundle.main.bundleIdentifier!)

… from netshark1000.

… except apparently removePersistentDomain doesn’t work when running tests. So maybe try this instead:

for key in Array(UserDefaults.standard.dictionaryRepresentation().keys) {
     UserDefaults.standard.removeObject(forKey: key)
}

… from bogen.

… or even just UserDefaults.standard.dictionaryRepresentation().keys.forEach(defaults.removeObject(forKey:)) from Naresh.