NSString: Get all matching NSRange of a substring

-rangesInSubstring:

- (NSArray *)rangesInSubstring:(NSString *)substring
{
    NSError *error = NULL;
    
    NSString *regex = [NSString stringWithFormat:@"\\b%@", substring];
    NSRegularExpression *regExpression = [NSRegularExpression regularExpressionWithPattern:regex options:NSRegularExpressionCaseInsensitive error:&error];
    
    NSMutableArray *ranges = [NSMutableArray array];
    
    NSArray *matches = [regExpression matchesInString:self options:NSRegularExpressionSearch range:NSMakeRange(0, self.length)];
    
    for (NSTextCheckingResult *match in matches) {
        [ranges addObject:[NSValue valueWithRange:match.range]];
    }
    
    return ranges;
}