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:
const validateCred = (array) => {
  // take second number from the array from the right and double it's value inside a double array
    const reverseArray = array.reverse();
    const found = reverseArray.map((e, i) => {
      if (i % 2 === 2 - 1) {
        let double = e * 2;
        if (double > 9) {
          return double - 9;
        }   return double;
      } return e;
    });
    const double2ndItemFromRight = found.reverse();
    //return double2ndItemFromRight;
    
    
  // now add double number inside an sum array
  const sum = double2ndItemFromRight.reduce((a,b) =>  a + b);
  
  // add values from the sum array and use % by 10.
  if(sum % 10 === 0) {
    return 'Valid';
  } return 'invalid';
  // if the remainder is zero then the card valid
};



const findInvalidCards = (invalid) => {
  let invalidCard = [];
  invalid.forEach(element => {
    //console.log(element)
    if(validateCred(element) === 'invalid') { 
    invalidCard.push(element.reverse()); 
    }
    
});
return invalidCard;
};


const idInvalidCardCompanies = (invalid2) => {
  let invalidCardCompanies = [];
  const invalidCards = findInvalidCards(invalid2);
  for(i in invalidCards) {
    if(invalidCards[i][0] == 3) {
      invalidCardCompanies.push('Amex')
    } else if(invalidCards[i][0] == 4) {
      invalidCardCompanies.push('Visa')
    } else if(invalidCards[i][0] == 5) {
      invalidCardCompanies.push('Mastercard')
    } else if(invalidCards[i][0] == 6) {
      invalidCardCompanies.push('Discover')
  } else {
    invalidCardCompanies.push('Company not found')}
}
  
  const noDuplicateCompanies = invalidCardCompanies.filter((v, i, a) => a.indexOf(v) === i);
  return noDuplicateCompanies;

}

console.log(idInvalidCardCompanies(batch));