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 = arr => {
    let newArray = [];
    //loop through the array in reverse order
    for(let i = arr.length-1; i>=0; i--){
        if(i%2 ==0){ //if i is an even number
            (arr[i]*2) > 9 ? newArray.push((arr[i]*2) - 9) : newArray.push(arr[i]*2)
        }else{
            newArray.push(arr[i])
        }
    }
    //uses reduce to sum all integers in the array
    const sum = newArray.reduce((a,b) => a + b)
    
    // if card is valid return true else return false
    return sum % 10 == 0 ? true : false
}

//filters out valid cards and returns an array of invalid cards
const findInvalidCards = invalidCards => 
    invalidCards.filter(arr => 
       validateCred(arr) == false
    )

const idInvalidCardCompanies = invalidCards => {
    let companies = []
    for(array in invalidCards){
        switch(invalidCards[array][0]){
            case 3:
                if(companies.indexOf("Amex") == -1){
                    companies.push("Amex")
                };
                break;
            case 4:
                if(companies.indexOf("Visa") == -1){
                    companies.push("Visa")
                };
                break;
            case 5: 
                if(companies.indexOf("Mastercard") == -1){
                    companies.push("Mastercard")
                }
                break;
            case 6:
                if(companies.indexOf("Discover") == -1){
                    companies.push("Discover")
                }
                break;
            default:
                console.log("Company not found");
                break;
        }
    }
    return companies
}

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