Regex golf, is this a valid PIN?

David Landry dlandry at
Mon Feb 24 07:33:04 MST 2014

Javascript, right?

On Mon, Feb 24, 2014 at 5:25 AM, S. Dale Morrey <sdalemorrey at>wrote:

> But I don't think it would work in a case where a pin starts with 0 would
> it?
For instance would 0123456789 return true or false with this?

Well, plugging it in to the Chrome Javascript console gives this:

> isPIN('0123456789')

Is there a better regex than this that could also do the trick?
> Is there extra cruft that could or ought to be eliminated? (my regex fu
> sucks bad)

There's a little bit of redundancy in there. Also, there's no length
requirement (e.g. isPIN('') also returns true).

Without adding length requirements, I'd do it like this:

  function isPIN(str) {
    return /^\+?(\d*)$/.test(str);

With a length requirement, it might look like this (if PINs must be 4
numbers long, {a,b} for a range from a to b length):

  function isPIN(str) {
    return /^\+?(\d{4})$/.test(str);

David Landry

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