credit-card-check.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 = (card) => {
    const checksum = [card.pop()]
    card.reverse().forEach((digit, index) => {
        if (index % 2 === 0) {
            if (digit < 5) {
                checksum.push(digit * 2)
            } else {
                checksum.push(digit * 2 - 9)
            }
        } else {
            checksum.push(digit)
        }
    })

    checksumTotal = checksum.reduce((acc, next) => acc += next)
    if (checksumTotal % 10 === 0) {
        return true
    }
    
    return false

}

const findInvalidCards = (cards) => {
    invalidCards = []
    cards.forEach(card => {
        if (!validateCred(card)) {
            invalidCards.push(card)
        }
    })
    return invalidCards
}

const idInvalidCardCompanies = (invalidCards) => {
    const invalidCompanies = new Set
    invalidCards.forEach(card => {
        switch (card[0]) {
            case 3:
                invalidCompanies.add('AMEX (American Expess)')
                break;
            case 4:
                invalidCompanies.add('Visa')
                break;
            case 5:
                invalidCompanies.add('Mastercard')
                break;
            case 6:
                invalidCompanies.add('Discover')
                break;
            default:
                invalidCompanies.add('Company not found')
                break;

        }
    })
    return Array.from(invalidCompanies)
}



console.log(validateCred(invalid1))
invalidCards = findInvalidCards(batch)
console.log(invalidCards.length)
console.log(idInvalidCardCompanies(invalidCards))

Solution to Codeacademy project.