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:
function validateCred(array) {
  let sum = 0;
  let parity = (array.length - 2) % 2;
  let digit;
  for (let i = array.length - 1; i >= 0; i--) {
    if (i % 2 == parity) {
      let double = array[i] * 2;
      if (double > 9) {
        digit = double - 9;
      } else {
        digit = double;
      }
    } else {
      digit = array[i];
    }
    sum = sum + digit;
  }
  

  return sum % 10 == 0;
}

function findInvalidCards(array) {
  let invalidCards = [];
  for (let arr of array) {
    const findInvalid = validateCred(arr);

    if (!findInvalid) {
      invalidCards.push(arr);
    }
  }
  return invalidCards;
}

function idInvalidCardCompanies(array) {
  const cardCompanies = {
    3: "Amex (American Express)",
    4: "Visa",
    5: "Mastercard",
    6: "Discover",
  };
  let invalidCardCompanies = [];
  for (let arr of array) {
    if (!cardCompanies[arr[0]]) {
      console.log("Company not found.");
    }
    invalidCardCompanies.push(cardCompanies[arr[0]]);
  }
  const invalidCardCompanyList = Array.from(new Set(invalidCardCompanies));
  return invalidCardCompanyList;
}