How to detect a property return type in Objective-C

Question

I have an object in objective-c at runtime, from which I only know the KVC key and I need to detect the return value type (e.g. I need to know if its an NSArray or NSMutable

Answer 1

The preferred way is to use the methods defined in the NSObject Protocol.

Specifically, to determine if something is either an instance of a class or of a subclass of that class, you use -isKindOfClass:. To determine if something is an instance of a particular class, and only that class (ie: not a subclass), use -isMemberOfClass:

So, for your case, you'd want to do something like this:

// Using -isKindOfClass since NSMutableArray subclasses should probably
// be handled by the NSMutableArray code, not the NSArray code
if ([anObject isKindOfClass:NSMutableArray.class]) {
    // Stuff for NSMutableArray here
} else if ([anObject isKindOfClass:NSArray.class]) {
    // Stuff for NSArray here

    // If you know for certain that anObject can only be
    // an NSArray or NSMutableArray, you could of course
    // just make this an else statement.
}