Phone number format

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
    NSString *newString = [textField.text stringByReplacingCharactersInRange:range withString:string];
    NSArray *components = [newString componentsSeparatedByCharactersInSet:[[NSCharacterSet decimalDigitCharacterSet] invertedSet]];
    NSString *decimalString = [components componentsJoinedByString:@""];

    NSUInteger length = decimalString.length;
    BOOL hasLeadingOne = length > 0 && [decimalString characterAtIndex:0] == '1';

    if (length == 0 || (length > 10 && !hasLeadingOne) || (length > 11)) {
        textField.text = decimalString;
        return NO;
    }

    NSUInteger index = 0;
    NSMutableString *formattedString = [NSMutableString string];

    if (hasLeadingOne) {
        [formattedString appendString:@"1 "];
        index += 1;
    }

    if (length - index > 3) {
        NSString *areaCode = [decimalString substringWithRange:NSMakeRange(index, 3)];
        [formattedString appendFormat:@"(%@) ",areaCode];
        index += 3;
    }

    if (length - index > 3) {
        NSString *prefix = [decimalString substringWithRange:NSMakeRange(index, 3)];
        [formattedString appendFormat:@"%@-",prefix];
        index += 3;
    }

    NSString *remainder = [decimalString substringFromIndex:index];
    [formattedString appendString:remainder];

    textField.text = formattedString;

    return NO;
}

(OR)

 [self.textField addTarget:self action:@selector(formatPhoneNumber) forControlEvents:UIControlEventEditingChanged];

#pragma mark - phone number formatting

- (void)formatPhoneNumber {

    

    NSString *currentString = self.textField.text;

    NSString *strippedValue = [currentString stringByReplacingOccurrencesOfString:@"[^0-9]" withString:@"" options:NSRegularExpressionSearch range:NSMakeRange(0, currentString.length)];

    NSString *formattedString;

    if (strippedValue.length == 0) {

        formattedString = @"";

    }

    else if (strippedValue.length < 3) {

        formattedString = [NSString stringWithFormat:@"(%@", strippedValue];

    }

    else if (strippedValue.length == 3) {

        formattedString = [NSString stringWithFormat:@"(%@) ", strippedValue];

    }

    else if (strippedValue.length < 6) {

        formattedString = [NSString stringWithFormat:@"(%@) %@", [strippedValue substringToIndex:3], [strippedValue substringFromIndex:3]];

    }

    else if (strippedValue.length == 6) {

        formattedString = [NSString stringWithFormat:@"(%@) %@-", [strippedValue substringToIndex:3], [strippedValue substringFromIndex:3]];

    }

    else if (strippedValue.length <= 10) {

        formattedString = [NSString stringWithFormat:@"(%@) %@-%@", [strippedValue substringToIndex:3], [strippedValue substringWithRange:NSMakeRange(3, 3)], [strippedValue substringFromIndex:6]];

    }

    else if (strippedValue.length >= 11) {

        formattedString = [NSString stringWithFormat:@"(%@) %@-%@ x%@", [strippedValue substringToIndex:3], [strippedValue substringWithRange:NSMakeRange(3, 3)], [strippedValue substringWithRange:NSMakeRange(6, 4)], [strippedValue substringFromIndex:10]];

    }

    

    self.textField.text = formattedString;

}