getCardBrand.js

// Based on http://en.wikipedia.org/wiki/Bank_card_number#Issuer_identification_number
// Card names used from tipsi-stripe.
const brandAmericanExpress = {
  name: 'American Express',
  prefixes: ['34', '37'],
}
const brandDiscover = {
  name: 'Discover',
  prefixes: ['60', '62', '64', '65'],
}
const brandJCB = {
  name: 'JCB',
  prefixes: ['35'],
}
const brandDinersClub = {
  name: 'Diners Club',
  prefixes: ['300', '301', '302', '303', '304', '305', '309', '36', '38', '39'],
}
const brandVisa = {
  name: 'Visa',
  prefixes: ['4'],
}
const brandMasterCard = {
  name: 'MasterCard',
  prefixes: [
    '2221', '2222', '2223', '2224', '2225', '2226', '2227', '2228', '2229',
    '223', '224', '225', '226', '227', '228', '229',
    '23', '24', '25', '26',
    '270', '271', '2720',
    '50', '51', '52', '53', '54', '55',
  ],
}

const brandsList = [
  brandVisa,
  brandMasterCard,
  brandAmericanExpress,
  brandDinersClub,
  brandDiscover,
  brandJCB,
]

function hasAnyPrefix(number, brandToCheck) {
  for (const prefix of brandToCheck.prefixes) {
    if (number.startsWith(prefix)) {
      return true
    }
  }
  return false
}

export default function getCardBrand(number) {
  const brand = brandsList.find(item => hasAnyPrefix(number, item))
  return brand ? brand.name : 'Unknown'
}