Hong Kong EPS Checksum

eps.js

function eps_checksum(accNumber) {
	return 10 - (accNumber.split("").map((digit, index) => digit*( Number((index+1)%2==0)+1) ).reduce((a,b)=> a+(b%10)+Number(b>10)) % 10 );
}

eps.php

<?php

function eps_checksum($data){
  $sum = 0;
  foreach(str_split($data) as $index => $item){
    $weight = (($index + 1) % 2 == 0) ? 2 : 1;
    $sum += array_sum(str_split(($item * $weight)));
  }
  return  10 - ( $sum % 10 );
}

?>