Codecademy export

main.js

// All valid credit card numbers
const valid1 = [4, 5, 3, 9, 6, 7, 7, 9, 0, 8, 0, 1, 6, 8, 0, 8];
const valid2 = [5, 5, 3, 5, 7, 6, 6, 7, 6, 8, 7, 5, 1, 4, 3, 9];
const valid3 = [3, 7, 1, 6, 1, 2, 0, 1, 9, 9, 8, 5, 2, 3, 6];
const valid4 = [6, 0, 1, 1, 1, 4, 4, 3, 4, 0, 6, 8, 2, 9, 0, 5];
const valid5 = [4, 5, 3, 9, 4, 0, 4, 9, 6, 7, 8, 6, 9, 6, 6, 6];

// All invalid credit card numbers
const invalid1 = [4, 5, 3, 2, 7, 7, 8, 7, 7, 1, 0, 9, 1, 7, 9, 5];
const invalid2 = [5, 7, 9, 5, 5, 9, 3, 3, 9, 2, 1, 3, 4, 6, 4, 3];
const invalid3 = [3, 7, 5, 7, 9, 6, 0, 8, 4, 4, 5, 9, 9, 1, 4];
const invalid4 = [6, 0, 1, 1, 1, 2, 7, 9, 6, 1, 7, 7, 7, 9, 3, 5];
const invalid5 = [5, 3, 8, 2, 0, 1, 9, 7, 7, 2, 8, 8, 3, 8, 5, 4];

// Can be either valid or invalid
const mystery1 = [3, 4, 4, 8, 0, 1, 9, 6, 8, 3, 0, 5, 4, 1, 4];
const mystery2 = [5, 4, 6, 6, 1, 0, 0, 8, 6, 1, 6, 2, 0, 2, 3, 9];
const mystery3 = [6, 0, 1, 1, 3, 7, 7, 0, 2, 0, 9, 6, 2, 6, 5, 6, 2, 0, 3];
const mystery4 = [4, 9, 2, 9, 8, 7, 7, 1, 6, 9, 2, 1, 7, 0, 9, 3];
const mystery5 = [4, 9, 1, 3, 5, 4, 0, 4, 6, 3, 0, 7, 2, 5, 2, 3];

// An array of all the arrays above
const batch = [valid1, valid2, valid3, valid4, valid5, invalid1, invalid2, invalid3, invalid4, invalid5, mystery1, mystery2, mystery3, mystery4, mystery5];


// Add your functions below:
const validateCred = (creditCardNumberArray) => {
  // using Luhn, Hans Peter's Algorithm
  let checkDigit = creditCardNumberArray[creditCardNumberArray.length - 1];
  let newCreditCardArray = creditCardNumberArray.slice(0, creditCardNumberArray.length-1);
  let length = newCreditCardArray.length;
  for(let i = 0; i <= length-1; i++) {
    newCreditCardArray[length - 1 - i] *= (i % 2 === 0) ? 2 : 1;
    if (newCreditCardArray[length - 1 - i] > 9) {
      newCreditCardArray[length - 1 - i] -= 9;
    }
  }
  newCreditCardArray.push(checkDigit);
  let checksum = newCreditCardArray.reduce((lastValue, newValue) => lastValue + newValue);
  return checksum % 10 === 0;
}

const findInvalidCards = (cards) => {
  let invalidCards = [];
  for (let card of cards) {
    if (validateCred(card) === false) {
      invalidCards.push(card);
    }
  }
  return invalidCards;
}

const invalidCards = findInvalidCards(batch);

const idInvalidCardCompanies = (invalidCards) => {
  const cardCompanies = ['Company not found', 'Company not found', 'Company not found', 'Amex (American Express)', 'Visa', 'Mastercard', 'Discover'];
  let invalidCardCompanies = [];
  for (let invalidCard of invalidCards) {
    if(!invalidCardCompanies.includes(cardCompanies[invalidCard[0]])) {
      invalidCardCompanies.push(cardCompanies[invalidCard[0]]);
    }
  }

  return invalidCardCompanies;
}

console.log(invalidCards);
console.log(idInvalidCardCompanies(invalidCards));