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(arr) {
  let total;
  let newArr = [];
  for (let i=arr.length-2;i>=0;i--) {
    newArr.push(arr[i]);
  }

  for (let i=0;i<=newArr.length-1;i++) {
    if (i%2==0) newArr[i] = 2*newArr[i];
    if (newArr[i] > 9) newArr[i]-=9;
  }

  total = newArr.reduce((p,c) => p + c,0);
  return (total + arr[arr.length-1]) % 10 == 0;
}

function findInvalidCards(arr) {
  let invalidCards = [];
  for (let i=0;i<arr.length;i++) {
    if (!validateCred(arr[i])) invalidCards.push(arr[i]);
  }
  return invalidCards;
}

function idInvalidCardCompanies(arr) {
  let companies = [];
  let companyName;
  for (let i=0;i<arr.length;i++) {
    switch (arr[i][0]) {
      case 3:
        companyName = "Amex (American Express)";
        break;
      case 4:
        companyName = "Visa";
        break;
      case 5:
        companyName = "Mastercard";
        break;
      case 6:
        companyName = "Discover";
        break;
      default:
        companyName = "Company not found";
        break;
    }
    if (!companies.includes(companyName)) companies.push(companyName);
  }
  return companies;
}