cards.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 = (array) => {
  let arrayCopy = array.slice();
  let sum = 0;
  for(let i = 0 ; i < arrayCopy.length ; i++){
   if(i%2==0){
     arrayCopy[i] = arrayCopy[i] * 2;
     if(arrayCopy[i] > 9){
       arrayCopy[i] = arrayCopy[i] - 9;
     }
   }
   sum = sum + arrayCopy[i];
}
   return sum % 10 === 0;

}



const findInvalidCards = (nestedArr) => {

    let invalidCard = [];

    for (let i = 0; i < nestedArr.length; i++) {

        if (validateCred(nestedArr[i]) === false) {

            invalidCard.push(nestedArr[i])
        }

    }

    return invalidCard
}


const idInvalidCardCompanies = (nestedArr) => {

    let invalidCompany = [];

    for (let i = 0; i < nestedArr.length; i++) {

        let iD = nestedArr[i][0];
        let name = '';

        switch (iD) {

            case 3:
                {
                    name = 'Amex (American Express';
                    break;
                }

            case 4:
                {
                    name = 'Visa';
                    break;
                }

            case 5:
                {
                    name = 'Mastercard';
                    break;
                }

            case 6:
                {
                    name = 'Discover';
                    break;
                }

            default:
                {
                    console.log(`Company not found for ${nestedArr[i]}`)
                    break;
                }
        }

        if (invalidCompany.indexOf(name) === -1) {
            invalidCompany.push(name)
        }


    }

    return invalidCompany
}