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,
];

const validateCred = (toValidate) => {
  let finalList = [];
  // Loop backwards
  for (let i = toValidate.length - 1; i >= 0; i -= 2) {
    let checkDigit = toValidate[i];
    let digitBeforeCheck = toValidate[i - 1];
    let digitBeforeCheckMultiplication =
      digitBeforeCheck * 2 > 9
        ? digitBeforeCheck * 2 - 9
        : digitBeforeCheck * 2;

    // Push checkDigit to list
    if (i === 0) {
      finalList.unshift(checkDigit);
    } else {
      finalList.unshift(digitBeforeCheckMultiplication, checkDigit);
    }
  }
  return (
    finalList.reduce((initialVal, currentVal) => initialVal + currentVal) %
      10 ===
    0
  );
};

const findInvalidCards = (cardsToCheck) =>
  cardsToCheck.filter((currentCardDet) => !validateCred(currentCardDet));

const idInvalidCardCompanies = (nestedInvalidCards) => {
  let cardCompanies = {
    3: "Amex (American Express)",
    4: "Visa",
    5: "Mastercard",
    6: "Discover",
  };

  let res = [];
  nestedInvalidCards.map((currentCard) => {
    let currentCardInitial = currentCard[0];

    if (currentCardInitial in cardCompanies) {
      let company = cardCompanies[currentCardInitial];
      res.includes(company) ? null : res.push(company);
    } else {
      console.log("Company not found");
    }
  });
  return res;
};