Objective-C

//  object being sorted
@interface ObjCObject : NSObject
@property (copy) NSString * name;
@property (strong) NSDate * date;

//  mutable array of the object
NSMutableArray * objects = ...

//  sort by object.date
[objects sortUsingComparator: ^NSComparisonResult( ObjCObject * object0,
                                                   ObjCObject * object1 )
{
	return [object0.date compare: object1.date];
}];

Swift

//  object being sorted
class SwiftObject
{
	var name = String()
	var date = NSDate()
}

//  mutable array of the object
var objects = ...

//  sort by object.date
objects.sort
{
	$0.date.timeIntervalSince1970 > $1.date.timeIntervalSince1970
}