Reverse string

Reverse

- (NSString *)reverse:(NSString *)source {
    if (!source) {
        return nil;
    }
    
    NSMutableString *reversed = [NSMutableString new];
    [source enumerateSubstringsInRange:NSMakeRange(0, [source length]) options:NSStringEnumerationReverse | NSStringEnumerationByComposedCharacterSequences usingBlock:^(NSString *substring, NSRange substringRange, NSRange enclosingRange, BOOL *stop) {
        [reversed appendString:substring];
    }];
    
    return reversed;
}