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 companies = {3 : "Amex", 4 : "Visa", 5 : "Mastercard", 6 : "Discover"}; //helper array for the companies

// Add your functions below:



function validateCred(arr)
{
  let double = false; //check if it needs to double the digit
  let sum = 0; //sum
  for(let i = arr.length - 1; i >= 0; i--) //loop through the digits in the array
  {
    sum += (double ? ((arr[i]*2) > 9 ? (arr[i]*2 - 9) : arr[i]*2) : (arr[i])); //checks if double is true, if so, double the number and check if its greater than nine, if so, subtract 9. If false, add the number in either case
    double = (double ? false : true); //toggle flag
  }
  return (sum % 10) === 0; //check the validity of the sum, return true/false if the remainder is 0
}

function findInvalidCards(nestedArr)
{
  let a = 0; //to aid the ternary operation
  let invalid = []; //resultant array
  nestedArr.forEach(function(arr){validateCred(arr) ? a = 0 : invalid.push(arr)}); //go through rach array, if valid, do nothing otherwise add to result array
  return invalid; //return array
}

function idInvalidCardCompanies(arrays)
{
  let a = 0; //to aid the ternary operation
  let invalidCompany = []; //resultant array
  arrays.forEach(function(arr){(invalidCompany.includes(companies[arr[0]])) ? a = 0 : invalidCompany.push(companies[arr[0]])}); //if the compnay is found but not incuded, add it to the resultant array. otherwise, do nothing
  return invalidCompany; //return array
}

//console.log(idInvalidCardCompanies(findInvalidCards(batch)));



batch.forEach(function(arr){console.log(validateCred(arr))});