Task

Validate the check digit of an ISBN-13 code:

   Multiply every other digit by  3.
   Add these numbers and the other digits.
   Take the remainder of this number after division by  10.
   If it is  0,   the ISBN-13 check digit is correct.


Use the following codes for testing:

   978-1734314502       (good)
   978-1734314509         (bad)
   978-1788399081       (good)
   978-1788399083         (bad)


Show output here, on this page



See also

   for details:   13-digit ISBN method of validation.       (installs cookies.)


fcn ISBN13_check(isbn){  // "978-1734314502", throws on invalid digits
   var [const] one3=("13"*6 + 1).split("").apply("toInt"); // examine 13 digits
   // one3=("13"*6) if you want to calculate what the check digit should be
   one3.zipWith('*,isbn - " -").sum(0) % 10 == 0
}