Credit Card Checker: Challenge project on Codecademy

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]


// Credit Card validation function
function validateCred(creditCard) {
    let sum = 0; // sum up numbers of the card
    let even = 1; // check every other number with the veriable
    let currentNumber;
    for (let i = creditCard.length - 1; i >= 0; i--) {
        if (even % 2 === 0) {
            currentNumber = creditCard[i] * 2;
            if (currentNumber > 9) {
                currentNumber -= 9;
            }
        } else {
            currentNumber = creditCard[i];
        }
        sum += currentNumber;
        even++;
    }
    return sum % 10 === 0;
}

// A function that takes a nested array of card numbers and returns another nested array of invalid numbers 
function findInvalidCards(arrayOfCards) {
    let invalidCards = [];
    for (let i = 0; i < arrayOfCards.length; i++) {
        if (!validateCred(arrayOfCards[i])) {
            invalidCards.push(arrayOfCards[i]);
        }
    }
    return invalidCards;
}

// Add all invalid cards to a separate nested array
let invalidCards = findInvalidCards(batch);

//check the companies that issued invalid cards
function idInvalidCardCompanies(arrayOfCards) {
    let invalidCardTypes = [];
    for (let i = 0; i < arrayOfCards.length; i++) {
        switch (arrayOfCards[i][0]) {
            case 3:
                if (!invalidCardTypes.includes('Amex (American Express)')) {
                    invalidCardTypes.push('Amex (American Express)');
                };
                break;
            case 4:
                if (!invalidCardTypes.includes('Visa')) {
                    invalidCardTypes.push('Visa');
                };
                break;
            case 5:
                if (!invalidCardTypes.includes('MasterCard')) {
                    invalidCardTypes.push('MasterCard');
                };
                break;
            case 6:
                if (!invalidCardTypes.includes('Discover')) {
                    invalidCardTypes.push('Discover');
                };
                break;
            default:
                if (!invalidCardTypes.includes('Company not found')) {
                    invalidCardTypes.push('Company not found');
                };
                break;
        };
    };

    return invalidCardTypes;
}

//convert a string of credit card number into an array
function convertToArray(cardNumberString) {
    let cardArray = [];
    if (typeof cardNumberString === 'number') {
        cardNumberString = cardNumberString.toString();
    }
    for (i = 0; i < cardNumberString.length; i++) {
        cardArray.push(parseInt(cardNumberString[i]));
    }
    return cardArray;
}

newCard = convertToArray(601111330051857);
console.log(newCard);
console.log(validateCred(newCard));