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:

// Putting the Luhn Algorithm into code
const validateCred = array => {
  let firstSum = 0;
  let skipped = 0;
  //Iterate backwards
  for (let i = array.length - 2; i >= 0; i-=2) {
    //console.log(array[i]);
    //Double every other digit in the card number
    let doubled = array[i] * 2;
    // If the doubled number is greater than 9, subtract 9
    if (doubled > 9) {
      doubled -= 9;
    }
    //Total up all doubled numbers and save under firstSum
    firstSum += doubled;
    //console.log(firstSum);
  }
  //Iterate again to catch all unused numbers
  for (let j = array.length - 1; j >= 0; j-=2){
    //console.log(array[j]);
    //Add all unused numbers to variable 'skipped'
    skipped += array[j];
  }
  //console.log(skipped);
  //Sum up all doubled numbers and skipped numbers
  let finalSum = firstSum + skipped;
  //console.log(finalSum);
  //If the final sum % 10 equals 0, the card number is valid
  if (finalSum % 10 === 0) {
    return true;
  } else {
    return false;
  }
}
//console.log(validateCred(valid1));

/*let knownInvalid = [invalid1, invalid2, invalid3, invalid4, invalid5];*/

//Set up empty array to hold invalid card numbers
let invalidCards = [];
const findInvalidCards = nestArray => {
  //Iterate through the nested array
  for (let i = 0; i < nestArray.length; i++) {
    //Run validateCred on each array in the array
    validateCred(nestArray[i]);
    //If the card number is invalid, add it to the invalidCards array
    if (validateCred(nestArray[i]) === false) {
      invalidCards.push(nestArray[i]);
    }
  }
  //Check the invalidCards array
  console.log(invalidCards);
}
findInvalidCards(batch);

//This function only works if you run the findInvalidCards function first and DON'T COMMENT IT OUT before you run idInvalidCardCompanies!!!
const idInvalidCardCompanies = invalidArray => {
  //Create new array containint all invalid cards
  let badCards = invalidCards;
  // Create array of companies to contact
  let contactCompanies = [];
  //Iterate through new array
  for (let i = 0; i < badCards.length; i++) {
    //Amex (American Express) cards start with 3
    if (badCards[i][0] === 3) {
      //Check if Amex is in contactCompanies array
      if (contactCompanies.indexOf('Amex') === -1) {
        //If not, add Amex to the list
        contactCompanies.push('Amex');
      }
      //Visa cards start with 4
    } else if (badCards[i][0] === 4) {
      //Check if Visa is in contactCompanies list
      if (contactCompanies.indexOf('Visa') === -1) {
        //If not, add to list
        contactCompanies.push('Visa');
      }
      //Mastercards start with 5
    } else if (badCards[i][0] === 5) {
      //Check if Mastercard is on contact list
      if (contactCompanies.indexOf('Mastercard') === -1) {
        //If not, add to list
        contactCompanies.push('Mastercard');
      }
      //Discover cards start with 6
    } else if (badCards[i][0] === 6) {
      //Check if Discover is on contact list
      if (contactCompanies.indexOf('Discover') === -1) {
        //If not, add to list
        contactCompanies.push('Discover');
      }
    } else {
      //If the first number is not on this list, log to screen "Company not found"
      console.log("Company not found");
    }
  }
  //Log to screen entire contactCompanies list
  console.log(contactCompanies);
}
idInvalidCardCompanies(invalidCards);