Validating password in JavaScript; RegEx

Question

On the system I am working with, we have a Password class that validates by throwing exceptions under the following conditions:

public Password(string password)
    : base(password)
{
    // Must contain digit, special character, or uppercase character

    var charArray = password.ToCharArray();

    var hasDigit = charArray.Select(c => char.IsDigit(c)).Any();
    var hasSpecialCharacter = charArray.Select(c => char.IsSymbol(c)).Any();
    var hasUpperCase = charArray.Select(c => char.IsUpper(c)).Any();

    if (!hasDigit && !hasSpecialCharacter && !hasUpperCase)
    {
        throw new ArgumentOutOfRangeException
             ("Must contain at least one digit, symbol, or upper-case letter.");
    }
}

If I was going to write this same check for hasDigit, hasSpecialCharater, and hasUpperCase in JavaScript, what would it look like?

JavaScript does not have these same character prototypes, so I've got to use regular expressions, no?

The Char.IsSymbol() is non-trivial to implement. (I just peeked into the mscorlib.dll using the RedGate reflector.) If you want your javascript and C# implementations to match precisely, you may be better off using the same regular expression on both the client and server. — dana
– dana, Commented Nov 9, 2010 at 21:42

kennytm · Accepted Answer · 2010-11-09 21:44:20Z

1

The three conditions can be combined together with:

if (/\d|\W|[A-Z]/.test(theString)) {
 ...

where

\d → 1 digit (0-9),
\W → 1 non-word character (anything except 0-9, a-z, A-Z and _) This matches more character than C#'s IsSymbol, in case the password supports characters outside of ASCII,
[A-Z] → 1 uppercase character

but the only characters which doesn't match \d|\W|[A-Z] are a to z, which we may as well simply write

if (/[^a-z]/.test(theString)) {

edited Nov 9, 2010 at 21:44

answered Nov 9, 2010 at 21:38

kennytm

526k110 gold badges1.1k silver badges1k bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

MartinodF Over a year ago

That's different from what the OP asked. You're checking if the password has a digit AND an uppercase AND a specialchar. He wants to check if it has at least one of the three.

MartinodF · Accepted Answer · 2010-11-09 21:39:12Z

1

hasDigit:

/\d/.test(password);

hasUpperCase:

/[A-Z]/.test(password);

hasSpecialCharacter:

/[^a-zA-Z0-9]/.test(password);

edit .test is much better than .match

edited Nov 9, 2010 at 21:39

answered Nov 9, 2010 at 21:36

MartinodF

8,2842 gold badges34 silver badges28 bronze badges

Comments

cdhowie · Accepted Answer · 2010-11-09 21:39:12Z

0

You should be able to combine all of the tests into one JS regex:

if (!passwordString.match(/[^a-z ]/)) {
    alert('Invalid password.');
    return false;
}

answered Nov 9, 2010 at 21:39

cdhowie

172k25 gold badges303 silver badges324 bronze badges

Collectives™ on Stack Overflow

Validating password in JavaScript; RegEx

3 Answers 3

1 Comment

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

1 Comment

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related