Working PHP Credit Card luhn check (preliminary credit card number validation)

luhn_check.php

// will update with suggestions

function luhnCheck($number): bool
{
    $number = preg_replace("/[^0-9]/", "", strval($number)); // convert to string and remove non numeric characters
    $sum = "";
    $revNumber = strrev($number);
    $len = strlen($number);

    for ($i = 0; $i < $len; $i++) {
        $sum .= $i & 1 ? $revNumber[$i] * 2 : $revNumber[$i];
    }

    return array_sum(str_split($sum)) % 10 === 0;
}