shortnumberformatter.php

См. документацию.

<?php
 
namespace Bitrix\Main\PhoneNumber;

class ShortNumberFormatter
{
    protected static $templates = [
        3 => 'x-xx',
        4 => 'xx-xx',
        5 => 'x-xx-xx',
        6 => 'xx-xx-xx',
        7 => 'xxx-xx-xx'
    ];

    public static function format(PhoneNumber $phoneNumber)
    {
        $rawNumber = $phoneNumber->getNationalNumber();
        $template = static::$templates[mb_strlen($rawNumber)];
        if(!$template)
        {
            return $rawNumber;
        }
 
        $pattern = preg_replace("/[^x]/", "", $template);
        $pattern = str_replace("x", "(\\d)", $pattern);
        $pattern = "/" . $pattern . "/";
        $i = 0;
        $format = preg_replace_callback(
            "/x/",
            function () use (&$i)
            {
                return "$" . ++$i;
            },
            $template
        );
 
        $result = preg_replace($pattern, $format, $rawNumber);
        if($phoneNumber->getExtensionSeparator())
        {
            $result .= $phoneNumber->getExtensionSeparator() . " " . $phoneNumber->getExtension();
        }
        return $result;
    }

    public static function isApplicable(PhoneNumber $phoneNumber)
    {
        if($phoneNumber->isValid() || $phoneNumber->hasPlus())
            return false;
 
        $rawNumber = $phoneNumber->getNationalNumber();
        return preg_match("/^\d{3,7}$/", $rawNumber);
    }
}