codecademy project

credit card checker

// 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 that validates a credit card number
const validateCred = (array) => {
  // boolean to determine whether to double current element when iterating through array
  let double = true;
  // value of each element
  let value;
  // total of added values
  let payloadTotal = 0;
  for (let i = array.length - 2; i >= 0; i--) {
    // if current value needs to be doubled
    if (double) {
      // value being doubled
      value = array[i] * 2;
      //console.log (`value doubled: ${value}`);
      // make sure next iteration the value gets doubled
      double = false;
      if (value > 9) {
        // value's digits add up when 9 is subtracted
        value -= 9;
      }
    } else {
      // value when not being doubled
      value = array[i];
      //console.log (`value: ${value}`);
      double = true;
    }
    // add current value to running total
    payloadTotal += value;
  }
  // add the check digit to the final sum
  payloadTotal += array[array.length - 1];
  //console.log(`payload total: ${payloadTotal}`);
  // performs modulo 10 on value of total to determine validity of credit card number
  let mod10 = payloadTotal % 10;
  //console.log (`module 10 = ${mod10}`);
  if (mod10 === 0) {
    // valid credit card number
    return true;
  } else {
    // invalid credit card number
    return false;
  }
};

validateCred(mystery3);

// function that finds invalid credit card numbers in an array
const findInvalidCards = (array) => {
  //array.forEach(element => validateCred(element));
  // array that will store credit card numbers found to be invalid
  let invalidBatch = [];
  // iterate through given array and validate credit card numbers
  array.forEach(function (element) {
    validateCred(element);
    // if validation functions returns false aka invalid credit card number..
    if (validateCred(element) === false) {
      // ..add the number to the invalid credit card number array
      invalidBatch.push(element);
    }
  });
  // return the array of invalid credit card numbers
  return invalidBatch;
};

findInvalidCards(batch);

// function to ID invalid credit card numbers
const idInvalidCardCompanies = (array) => {
  // array to store all the invalid credit card numbers
  let invalidCardBatch = findInvalidCards(batch);
  // array of companies that have been found to have issued invalid credit card numbers
  let invalidCardCompanies = [];
  // iterate through array of..
  array.forEach(function (element) {
    // ..invalid credit card numbers
    invalidCardBatch[element];
    // if the first number of credit card number is 3, credit card company is Amex
    if (element[0] === 3 && !invalidCardCompanies.includes("Amex")) {
      invalidCardCompanies.push("Amex");
      // if the first number of credit card number is 4, credit card company is Visa
    } else if (element[0] === 4 && !invalidCardCompanies.includes("Visa")) {
      invalidCardCompanies.push("Visa");
      // if the first number of credit card number is 5, credit card company is Mastercard
    } else if (
      element[0] === 5 &&
      !invalidCardCompanies.includes("Mastercard")
    ) {
      invalidCardCompanies.push("Mastercard");
      // if the first number of credit card number is 6, credit card company is Discover
    } else if (element[0] === 6 && !invalidCardCompanies.includes("Discover")) {
      invalidCardCompanies.push("Discover");
      // if none of the previous criteria are not met, company is unknown
    } else if (
      element[0] !== 3 &&
      element[0] !== 4 &&
      element[0] !== 5 &&
      element[0] !== 6
    ) {
      invalidCardCompanies.push("Company not found");
    }
  });
  // return array of credit card companies that issued invalid numbers
  return invalidCardCompanies;
};

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

const convertInvalid = (array) => {
  let invalidConverted = [];
 // boolean to determine whether to double current element when iterating through array
  let double = true;
  // value of each element
  let value;
  // total of added values
  let payloadTotal = 0;
  for (let i = array.length - 2; i >= 0; i--) {
    // if current value needs to be doubled
    if (double) {
      // value being doubled
      value = array[i] * 2;
      //console.log (`value doubled: ${value}`);
      // make sure next iteration the value gets doubled
      double = false;
      if (value > 9) {
        // value's digits add up when 9 is subtracted
        value -= 9;
      }
    } else {
      // value when not being doubled
      value = array[i];
      //console.log (`value: ${value}`);
      double = true;
    }
    // add current value to running total
    payloadTotal += value;
  }
  // add the check digit to the final sum
  payloadTotal += array[array.length - 1];
  //console.log(`payload total: ${payloadTotal}`);
  // performs modulo 10 on value of total to determine validity of credit card number
  let mod10 = payloadTotal % 10;
  // invalid credit card number
  console.log(`Invalid credit card number: ${array}`);
  // modulo 10 value of invalid credit card number
  console.log (`modulo 10 = ${mod10}`);
  for (let i = array.length - 2; mod10 >= 0; i--) {
    if (mod10 === 0) {
      // new and improved, valid credit card number
      console.log(`Valid credit card number: ${array}`);
      // modulo 10 value of valid credit card number
      console.log (`modulo 10 = ${mod10}`);
      return true;
    }
  if (array[i] <= 8) {
    array[i] ++;
    mod10 --;
  } 
  }
  };

console.log(convertInvalid(invalid1));