ericmbarnard/Knockout-Validation — pull request #234 by JoeDoyle23 (2013-02-25 18:26:16+00:00)
Title: Allow phoneUS rule to pass when observable value is null

We ran into a situation where we had a non-required phone number that we wanted validated, but the source value was null instead of empty. This caused the type check on line 620 to fail and the validation to then fail.

The change is to simply check for null first, then the type of the value.

A test was added to the suite as well.