Swift, NSJSONSerialization and NSError

Question

The problem is when there is incomplete data NSJSONSerialization.JSONObjectWithData is crashing the application giving unexpectedly found nil while unwrappin

Answer 1

Here is a Swift 2 extension you can use to deserialise only an NSDictionary:

extension NSJSONSerialization{
    public class func dictionaryWithData(data: NSData, options opt: NSJSONReadingOptions) throws -> NSDictionary{
        guard let d: NSDictionary = try self.JSONObjectWithData(data, options:opt) as? NSDictionary else{
            throw NSError(domain: NSURLErrorDomain, code: NSURLErrorCannotParseResponse, userInfo: [NSLocalizedDescriptionKey : "not a dictionary"])
        }
        return d;
    }
}

Sorry I wasn't sure how to do a guard return to avoid creating the temporary 'd'.