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(creditCard) {
  cred = [...creditCard]
  let temp = []
  // 1. Drop the check digit, it is most often the last digit
  temp.push(cred.pop())
  for (let i = cred.length - 1; i >= 0; i--) {
    // 2. Starting with the rightmost digit, double every other value
    if ((cred.length - 1 - i) % 2 === 0) {
      let dblValue = cred[i] * 2
      if (dblValue > 9) {
        dblValue -= 9
      }
      temp.push(dblValue)
    } else {
      temp.push(cred[i])
    }
  }

  //  3. Sum all the digits of the creditcard number
  const total = temp.reduce((acc, curr) => acc + curr, 0)

  // 4. For a valid card, the sum divided by 10 produces a remainder of 0
  if (total % 10 === 0) {
    return true
  } else {
    return false
  }
}

function findInvalidCards(creditCardList) {
  let invalidCards = []
  for (let creditCard of creditCardList) {
    if (!validateCred(creditCard)) {
      invalidCards.push(creditCard)
    }
  }

  return invalidCards
}

function idInvalidCardCompanies(invalidCards) {
  let possiblyCompanies = []

  for (let invalidCard of invalidCards) {
    switch (invalidCard[0]) {
      case 3:
        if (possiblyCompanies.findIndex(company => company === 'Amex') === -1) {
          possiblyCompanies.push('Amex')
        }
        break
      case 4:
        if (possiblyCompanies.findIndex(company => company === 'Visa') === -1) {
          possiblyCompanies.push('Visa')
        }
        break
        case 5:
        if (possiblyCompanies.findIndex(company => company ==='Mastercard') === -1) {
          possiblyCompanies.push('Mastercard')
        }
        break
        case 6:
        if (possiblyCompanies.findIndex(company => company ==='Discover') === -1) {
          possiblyCompanies.push('Discover')
        }
        break
      default:
        console.log('Company not found')
        break
    }
  }
  return possiblyCompanies
}