NSErrorPointerWrapper

Wrapper for handling iOS SDK APIs that take in error by reference.

Some of the benefits:

• Simplified handling of methods that take in NSErrorPoint.
• No more declaring that pesky NSError variable to pass by reference (use $0 shorthand argument name in closure passed to the wrapper).
• Chaining handlers for success and failure.
• Streamlined downcasting handling (needed because often the result of those methods is AnyObject? instance).

Usage

tryWithErrorPointer { NSJSONSerialization.JSONObjectWithData(data, options: nil, error: $0) }
                .onError { error in /* handle error */ }
                .onSuccess { result in /* handle success */ } }

With casting:

tryWithErrorPointer(castResultTo: NSDictionary.self) { NSJSONSerialization.JSONObjectWithData(data, options: nil, error: $0) }
                .onError { error in /* handle error */ }
                .onSuccess { result in /* handle success */ } }

For more details check tests and those resources:

• NSErrorPointerWrapper: Simplified handling of Cocoa Touch API errors in Swift,
• sample app: swift-objc.io-issue-10-core-data-network-application.

Installation with CocoaPods

• You need to use CocoaPods version that supports Frameworks: at least 0.36.0. Currently it's a beta feature, to install it update CocoaPods: gem install cocoapods --prerelease.
• Just add the following line to the Podfile and run pod update:

pod 'NSErrorPointerWrapper'