Checking a null value in Objective-C that has been returned from a JSON string

Question

I have a JSON object that is coming from a webserver.

The log is something like this:

{          
   \"status\":\"success\",
   \"Us         


        

Answer 1

If you are dealing with an "unstable" API, you may want to iterate through all the keys to check for null. I created a category to deal with this:

@interface NSDictionary (Safe)
-(NSDictionary *)removeNullValues;
@end

@implementation NSDictionary (Safe)

-(NSDictionary *)removeNullValues
{
    NSMutableDictionary *mutDictionary = [self mutableCopy];
    NSMutableArray *keysToDelete = [NSMutableArray array];
    [mutDictionary enumerateKeysAndObjectsUsingBlock:^(id key, id obj, BOOL *stop) {
        if (obj == [NSNull null]) 
        {
            [keysToDelete addObject:key];
        }
    }];
    [mutDictinary removeObjectsForKeys:keysToDelete];
    return [mutDictinary copy];
}
@end