type.js

module.exports = function detectCardType(cardNumber) {
  var card = cardNumber.toString().replace(/[^\d]/g, '');
  var result;
  var types = {
    electron: /^(4026|417500|4405|4508|4844|4913|4917)\d+$/,
    maestro: /^(5018|5020|5038|5612|5893|6304|6759|6761|6762|6763|0604|6390)\d+$/,
    dankort: /^(5019)\d+$/,
    interpayment: /^(636)\d+$/,
    unionpay: /^(62|88)\d+$/,
    visa: /^4[0-9]{12}(?:[0-9]{3})?$/,
    mastercard: /^5[1-5][0-9]{14}$/,
    amex: /^3[47][0-9]{13}$/,
    diners: /^3(?:0[0-5]|[68][0-9])[0-9]{11}$/,
    discover: /^6(?:011|5[0-9]{2})[0-9]{12}$/,
    jcb: /^(?:2131|1800|35\d{3})\d{11}$/,
    forbrugsforeningen: /^(600)\d+$/,
    mir: /^220[0-4][0-9][0-9]\d{10}$/
  };

  for (var type in types) {
    if (types[type].test(card)) {
      result = type.toString();
    }
  }

  return result;
};