TouchJSON, dealing with NSNull

Question

Hi I am using TouchJSON to deserialize some JSON. I have been using it in the past and on those occasions I dealt with occurrences of NSNull manually. I would think the auth

Answer 1

nil and NULL are actually both equal to zero, so they are, in practice, interchangeable. But you're right, for consistency, the documentation for TouchJSON should have used theDeserializer.nullObject = nil instead of NULL.

Now, when you do that, your second predicate actually works fine:

if (![jsonDataDict objectForKey:someKey])

because TouchJSON omits the key from the dictionary when you have nullObject set to nil (or NULL). When the key doesn't exist in the dictionary, NSDictionary returns nil, which is zero so your if condition works as you expect.

If you don't specify nullObject as nil, you can instead check for null like so:

if ([jsonDataDict objectForKey:someKey] == [NSNull null])