NSArray+Safe.h

//
//  NSArray+Safe.h
//  NNSafeArray
//
//  Created by Nguyen Hoang Nam on 15/3/16.
//  Copyright © 2016 Alan Nguyen. All rights reserved.
//

#import <Foundation/Foundation.h>

@interface NSArray(Safe)
- (void)setObject:(id)obj atIndexedSubscript:(NSUInteger)idx;
- (id)objectAtIndexedSubscript:(NSUInteger)index;
@end

NSArray+Safe.m

//
//  NSArray+Safe.m
//  NNSafeArray
//
//  Created by Nguyen Hoang Nam on 15/3/16.
//  Copyright © 2016 Alan Nguyen. All rights reserved.
//

#import "NSArray+Safe.h"

@implementation NSArray(Safe)

- (id)objectAtIndexedSubscript:(NSUInteger)index {
    return [self safeObjectForIndex:index];
}

- (id)safeObjectForIndex:(NSUInteger)index {
    if ( index >= self.count) {
        return nil;
    }
    id object = [self objectAtIndex:index];
    if ([object isKindOfClass:[NSNull class]] || !object) return nil;
    else return object;
}

- (void)setObject:(id)object atIndexedSubscript:(NSUInteger)idx {
    if ([object isKindOfClass:[NSNull class]] || !object) {
        return;
    } else {
        self[idx] = object;
    }
}

@end