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iOS Build a Weather App with Swift (Retired) Concurrency Using Our JSON Data

David Liu
David Liu
2,255 Points
Posted by David Liu
David Liu
2,255 Points

What does the "options" part of the completion handler actually do?

e.g.

let weatherDictionary: NSDictionary = NSJSONSerialization.JSONObjectWithData(dataObject!, options: nil, error: nil) as! NSDictionary

In this code, what can we put instead of "nil" for options? What is the function of it?

1 Answer

kjvswift93
kjvswift93
13,515 Points

You could replace nil with a reference to a made up optional object that doesn't exist, such as options: madeUpObject?. This would compile without an error because the compiler believes that madeUpObject could in fact exist or could be missing, due to the use of the ?. But doing that is meaningless. It is much clearer and effective to simply use nil, to let the compiler know that there is nothing there.