NSString category for finding the composed-character length. Practical use for most locales is finding the display-length of an emoji-containing string. ✨

NSString+KKEmojiHandling.h

@interface NSString (KKEmojiHandling)

- (NSUInteger)KK_composedLength;

@end

NSString+KKEmojiHandling.m

@implementation NSString (KKEmojiHandling)

- (NSUInteger)KK_composedLength
{
    __block NSUInteger length = 0;
    [self enumerateSubstringsInRange:NSMakeRange(0, self.length) options:NSStringEnumerationByComposedCharacterSequences usingBlock:^(NSString *substring, NSRange substringRange, NSRange enclosingRange, BOOL *stop) {
        length++;
    }];

    return length;
}

@end