Codecademy Credit Card Checker Project

CreditCardChecker

// 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 for calculating module
function validateCred (arr) {
  
  let tempArr = [...arr];
  
  //to reverse the array
  let reversedArr = tempArr.reverse();

  //to iterate trough every other index
    for (let i=1; i<reversedArr.length; i+=2) {
      if (reversedArr[i]<=4) reversedArr[i] = reversedArr[i] * 2
      else if (reversedArr[i]>4) reversedArr[i] = reversedArr[i] * 2 - 9;
    }
  
  //to sum the array and modulo
  let sum = reversedArr.reduce((a, b) => a + b);
  let modulo = sum % 10; 
  return modulo
  
};

//function to check the code
function findInvalidCards (nestedArr) {
  let invalidCards = [];
  for (let j=0; j<nestedArr.length; j++) {
    validateCred(nestedArr[j]);
    if (validateCred(nestedArr[j]) !=0 ) {
      invalidCards.push(nestedArr[j]);
    }
  };
  return invalidCards;
};

console.log('Invalid credit card numbers:')
console.log(findInvalidCards(batch));

//function to match the number with the bank
function idInvalidCardCompanies (invalidArr) {
  let companyArr = [];
  for (let k=0; k<invalidArr.length; k++) {
    switch (invalidArr[k][0]) {
      case 3:
        if (companyArr.indexOf('Amex (American Express)') === -1) companyArr.push('Amex (American Express)');
      break;
      case 4:
      if (companyArr.indexOf('Visa') === -1) companyArr.push('Visa');
      break;
      case 5:
      if (companyArr.indexOf('Mastercard') === -1) companyArr.push('Mastercard');
      break;
      case 6:
      if (companyArr.indexOf('Discover') === -1) companyArr.push('Discover');
      break;
      default: console.log('Company not found');
    }
  }
  return companyArr;
}
console.log('Credit card companies issuing faulty numbers:')
console.log(idInvalidCardCompanies(batch));