# Credit Card Checker

Hi fellas,

My mind is about to blow now from headache )) I’ve been trying to find a bug whole day, but my attempts were unsuccessful. I need your help at this moment for this project: https://www.codecademy.com/practice/projects/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]

const validateCred = (array)=> {
let tempArrSub = []; //Holds values of the 9 subtracted from doubled elements bigger than 9
let tempArr = array; //Copies the values of the array passed into parameters
tempArr.pop();
tempArr.reverse();

for (let i = tempArr.length-1; i >=0; i-=2){ //Doubles every two elements from right to left
tempArr[i] *= 2;
}

for (let k = 0; k < tempArr.length; k++) { //Subtract 9 from every second element (right to left) if bigger than 9
if (tempArr[k] > 9){
tempArrSub.push(tempArr[k] - 9);
}
else {
tempArrSub.push(tempArr[k]);
}
}

let tempArrSum = 0;

for (let m = 0; m < tempArrSub.length; m++){ //Calculates the sum of all elements in the array
tempArrSum += tempArrSub[m];
}

tempArrSum += array.pop(); //Adds the last digit of initial array to the sum

if (tempArrSum % 10 === 0) { //Returns true if the sum is divisible by 10
return true;
}
else {
return false;
}

} //End Of Function

const findInvalidCards = (nestedArray) => {
let invalidCards = [];
let validCards = [];
for (let a = 0; a < nestedArray.length; a++){

if ( validateCred(nestedArray[a]) ) {
validCards.push(nestedArray[a]);
}
else {
invalidCards.push(nestedArray[a]);
}
}

console.log("Invalid cards: \n" + invalidCards);
console.log("Valid cards: \n" + validCards);
}
``````

I tested each credit card array with validateCred() function. It is working fine, returning true or false. Then I tried to check nested ‘batch’ array with findInvalidCards() function by calling validateCred() function inside. It is returning true for the 1st card and false for all remaining cards. This is the last version of my code now. Many thanks for your help in advance!

`let tempArr = array;` is not creating a new array. It’s simply copying the reference to the array not a new copy of the array itself. Here is some reading you could do to better understand

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