credit card validator

validateCreditCardNumber.js

'use strict';
// https://stackoverflow.com/questions/72768/how-do-you-detect-credit-card-type-based-on-number/72801

const validate = (num) => (num
  .replace(/\D/g, ``) // strip all non-digit chars
  .split(``) // make an array where each digit is an element
  .map((n) => Number(n)) // make them all numbers
  .reverse() // reverse the order
  .reduce((checksum, n, i) =>
    (i % 2) ? checksum + n : checksum + (n * 2), 0) % 10) === 0;

const good = [
  `1111 2222 3333 4444`,
  `1111222233334444`,
  `1111-2222-3333-4444`
].map((n) => ({ n, valid: validate(n) }));

const bad = [
  `1111 2222 3333 4444 55`,
  `111122223333444455`,
  `1111-2222-3333-4444-55`
].map((n) => ({ n, valid: validate(n) }));;

console.log(`good\n`, good);
console.log(`bad\n`, bad);