How To: custom Validator for Phone USA

[[!FormIt?  &customValidators=`isPhone` &validate=`phone:isPhone`]]

<?php

$value;

$pattern = "/^\(?(\d{3})\)?[- ]?(\d{3})[- ]?(\d{4})$/";

/*** try to validate with the regex pattern ***/
if(filter_var($value, FILTER_VALIDATE_REGEXP, array("options"=>array("regexp"=>$pattern))) === false)
        {
        return $value;
        }
?>