chriso/node-validator — pull request #90 by datarem (2012-06-20 00:03:41+00:00)
Title: Added luhn check to isCreditCard.

Works will all numbers given here http://www.paypalobjects.com/en_US/vhelp/paypalmanager_help/credit_card_numbers.htm except the shorter Dankort processor card which does not actually pass the luhn check.

http://en.wikipedia.org/wiki/Luhn_algorithm