NSArray+SafeAccess.h

#import <Foundation/Foundation.h>

@interface NSArray (SafeAccess)

- (instancetype)withoutNulls;
- (instancetype)arrayByRemovingObjectsOfClass:(id)obj;

- (id)objectAtIndex:(NSUInteger)index ifKindOf:(Class)kind;
- (id)objectAtIndex:(NSUInteger)index ifKindOf:(Class)kind defaultValue:(id)defaultValue;

- (NSArray*)arrayAtIndex:(NSUInteger)index;
- (NSArray*)arrayAtIndex:(NSUInteger)index defaultValue:(NSArray*)defaultValue;
- (NSDictionary*)dictionaryAtIndex:(NSUInteger)index;
- (NSDictionary*)dictionaryAtIndex:(NSUInteger)index defaultValue:(NSDictionary*)defaultValue;
- (NSString*)stringAtIndex:(NSUInteger)index;
- (NSString*)stringAtIndex:(NSUInteger)index defaultValue:(NSString*)defaultValue;
- (NSNumber*)numberAtIndex:(NSUInteger)index;
- (NSNumber*)numberAtIndex:(NSUInteger)index defaultValue:(NSNumber*)defaultValue;
// -boolAtIndex: is not provided. You are the owner of your default value mistakes.
- (BOOL)boolAtIndex:(NSUInteger)index defaultValue:(BOOL)defaultValue;
- (NSDate*)dateAtIndex:(NSUInteger)index;
- (NSDate*)dateAtIndex:(NSUInteger)index defaultValue:(NSDate*)defaultValue;

@end

NSArray+SafeAccess.m

#import "NSArray+SafeAccess.h"

@implementation NSArray (SafeAccess)

- (instancetype)withoutNulls
{
    NSArray* temp = [self arrayByRemovingObjectsOfClass:[NSNull class]];
    NSMutableArray* result = [NSMutableArray arrayWithCapacity:[temp count]];
    for(id obj in temp)
    {
        if([obj respondsToSelector:@selector(withoutNulls)])
            [result addObject:[obj withoutNulls]];
        else
            [result addObject:obj];
    }

    return [result copy];
}

- (instancetype)arrayByRemovingObjectsOfClass:(Class)aClass
{
    NSMutableArray* results = [NSMutableArray array];

    for(id o in self)
    {
        if([o isKindOfClass:aClass] == NO)
            [results addObject:o];
    }

    return [results copy];
}

- (id)objectAtIndex:(NSUInteger)index ifKindOf:(Class)kind
{
    return [self objectAtIndex:index ifKindOf:kind defaultValue:nil];
}

- (id)objectAtIndex:(NSUInteger)index ifKindOf:(Class)kind defaultValue:(id)defaultValue
{
    id obj = self[index];
    return [obj isKindOfClass:kind] ? obj : defaultValue;
}

#pragma mark - Type specific helpers

- (NSArray*)arrayAtIndex:(NSUInteger)index
{
    return [self arrayAtIndex:index defaultValue:@[]];
}

- (NSArray*)arrayAtIndex:(NSUInteger)index defaultValue:(NSArray*)defaultValue
{
    return [self objectAtIndex:index ifKindOf:[NSArray class] defaultValue:defaultValue];
}

- (NSDictionary*)dictionaryAtIndex:(NSUInteger)index
{
    return [self dictionaryAtIndex:index defaultValue:@{}];
}

- (NSDictionary*)dictionaryAtIndex:(NSUInteger)index defaultValue:(NSDictionary*)defaultValue
{
    return [self objectAtIndex:index ifKindOf:[NSDictionary class] defaultValue:defaultValue];
}

- (NSString*)stringAtIndex:(NSUInteger)index
{
    return [self stringAtIndex:index defaultValue:@""];
}

- (NSString*)stringAtIndex:(NSUInteger)index defaultValue:(NSString*)defaultValue
{
    return [self objectAtIndex:index ifKindOf:[NSString class] defaultValue:defaultValue];
}

- (NSNumber*)numberAtIndex:(NSUInteger)index
{
    return [self numberAtIndex:index defaultValue:nil];
}

- (NSNumber*)numberAtIndex:(NSUInteger)index defaultValue:(NSNumber*)defaultValue
{
    return [self objectAtIndex:index ifKindOf:[NSNumber class] defaultValue:defaultValue];
}

- (BOOL)boolAtIndex:(NSUInteger)index defaultValue:(BOOL)defaultValue
{
    NSNumber* defVal = @(defaultValue);
    return [[self objectAtIndex:index ifKindOf:[NSNumber class] defaultValue:defVal] boolValue];
}

- (NSDate*)dateAtIndex:(NSUInteger)index
{
    return [self dateAtIndex:index defaultValue:nil];
}

- (NSDate*)dateAtIndex:(NSUInteger)index defaultValue:(NSDate*)defaultValue
{
    return [self objectAtIndex:index ifKindOf:[NSDate class] defaultValue:defaultValue];
}

@end

NSDictionary+SafeAccess.h

#import <Foundation/Foundation.h>

@interface NSDictionary (SafeAccess)

- (instancetype)withoutNulls;

- (id)objectForKey:(id)key ifKindOf:(Class)kind;
- (id)objectForKey:(id)key ifKindOf:(Class)kind defaultValue:(id)defaultValue;

- (NSArray*)arrayForKey:(id)key;
- (NSArray*)arrayForKey:(id)key defaultValue:(NSArray*)defaultValue;
- (NSDictionary*)dictionaryForKey:(id)key;
- (NSDictionary*)dictionaryForKey:(id)key defaultValue:(NSDictionary*)defaultValue;
- (NSString*)stringForKey:(id)key;
- (NSString*)stringForKey:(id)key defaultValue:(NSString*)defaultValue;
- (NSNumber*)numberForKey:(id)key;
- (NSNumber*)numberForKey:(id)key defaultValue:(NSNumber*)defaultValue;
// -boolForKey: is not provided. You are the owner of your default value mistakes.
- (BOOL)boolForKey:(id)key defaultValue:(BOOL)defaultValue;
- (NSDate*)dateForKey:(id)key;
- (NSDate*)dateForKey:(id)key defaultValue:(NSDate*)defaultValue;

@end

NSDictionary+SafeAccess.m

#import "NSDictionary+SafeAccess.h"

@implementation NSDictionary (SafeAccess)

- (instancetype)withoutNulls
{
    NSMutableDictionary* replaced = [NSMutableDictionary dictionaryWithDictionary:self];
    NSString* blank = @"";

    for(NSString* key in self)
    {
        id object = [self objectForKey:key];
        if([object isKindOfClass:[NSNull class]] == YES)
            [replaced setObject:blank forKey:key];
        else if([object isKindOfClass:[NSDictionary class]] == YES)
            [replaced setObject:[(NSDictionary*)object withoutNulls] forKey:key];
    }
    return [NSDictionary dictionaryWithDictionary: replaced];
}

- (id)objectForKey:(id)key ifKindOf:(Class)kind
{
    return [self objectForKey:key ifKindOf:kind defaultValue:nil];
}

- (id)objectForKey:(id)key ifKindOf:(Class)kind defaultValue:(id)defaultValue
{
    id obj = self[key];
    return [obj isKindOfClass:kind] ? obj : defaultValue;
}

#pragma mark - Type specific helpers

- (NSArray*)arrayForKey:(id)key
{
    return [self arrayForKey:key defaultValue:@[]];
}

- (NSArray*)arrayForKey:(id)key defaultValue:(NSArray*)defaultValue
{
    return [self objectForKey:key ifKindOf:[NSArray class] defaultValue:defaultValue];
}

- (NSDictionary*)dictionaryForKey:(id)key
{
    return [self dictionaryForKey:key defaultValue:@{}];
}

- (NSDictionary*)dictionaryForKey:(id)key defaultValue:(NSDictionary*)defaultValue
{
    return [self objectForKey:key ifKindOf:[NSDictionary class] defaultValue:defaultValue];
}

- (NSString*)stringForKey:(id)key
{
    return [self stringForKey:key defaultValue:@""];
}

- (NSString*)stringForKey:(id)key defaultValue:(NSString*)defaultValue
{
    return [self objectForKey:key ifKindOf:[NSString class] defaultValue:defaultValue];
}

- (NSNumber*)numberForKey:(id)key
{
    return [self numberForKey:key defaultValue:nil];
}

- (NSNumber*)numberForKey:(id)key defaultValue:(NSNumber*)defaultValue
{
    return [self objectForKey:key ifKindOf:[NSNumber class] defaultValue:defaultValue];
}

- (BOOL)boolForKey:(id)key defaultValue:(BOOL)defaultValue
{
    NSNumber* defVal = @(defaultValue);
    return [[self objectForKey:key ifKindOf:[NSNumber class] defaultValue:defVal] boolValue];
}

- (NSDate*)dateForKey:(id)key
{
    return [self dateForKey:key defaultValue:nil];
}

- (NSDate*)dateForKey:(id)key defaultValue:(NSDate*)defaultValue
{
    return [self objectForKey:key ifKindOf:[NSDate class] defaultValue:defaultValue];
}

@end