Credit Card Checker Challenge Project (Codecademy)

creditchecker.js

// All valid credit Set 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 Set 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:
function sumArray(numberSet)
{
	let sum = 0;
	numberSet.forEach(element => {
		sum += element;
	});
	return sum;
}

//function validateCred uses the Luhn algorithm to determine whether a number is valid or not.
function validateCred(inputArray)
{
	let everyOther = true; //we'll use this to go through every other element (not each one)
	for (let i = inputArray.length-2; i >= 0; i--) //we start at the second-to-last element in the array
	{
		if (everyOther === true)
		{
			inputArray[i] *= 2; //multiply the element by two.  if the result is higher than 9, subtract 9 from it.
			if (inputArray[i] > 9)
			{
				inputArray[i] -= 9;
			}
		}
		everyOther = !everyOther; //flip everyOther
	}
	let inputSum = sumArray(inputArray);
	if (inputSum % 10 === 0)
	{
		return true;
	} else
	{
		return false;
	}
}

// console.log(validateCred(invalid1));
// console.log(validateCred(invalid2));
// console.log(validateCred(invalid3));
// console.log(validateCred(invalid4));
// console.log(validateCred(invalid5));

function findInvalidSets(testSet)
{
	let outputArray = [];
	for (let i = 0; i < testSet.length; i++)
	{
		let currentSet = testSet[i];
		if (validateCred(currentSet) === false)
		{
			outputArray.push(currentSet);
		}
	}
	return outputArray;
}

function idInvalidCardCompanies(inputArray)
{
	let companies = [];
	inputArray.forEach(function(element)
	{
		switch(element[0]) {
			case 3:
				if (companies.includes('Amex'))
				{
					break;
				} else
				{
					companies.push('Amex');
					break;
				}
			case 4:
				if (companies.includes('Visa'))
				{
					break;
				} else
				{
					companies.push('Visa');
					break;
				}
			case 5:
			if (companies.includes('Mastercard'))
			{
				break;
			} else
			{
				companies.push('Mastercard');
				break;
			}
			case 6:
				if (companies.includes('Discover'))
				{
					break;
				} else
				{
					companies.push('Discover');
					break;
				}
			default:
				companies.push("Unknown");
		}
	})
	return companies;
}

console.log(idInvalidCardCompanies(batch));