How would a person go about implenting a validation on a field using the luhnCheck?
function luhnCheck(number) {
number = String(number);
let sum = parseInt(number.charAt(number.length - 1));
for (let i = 0; i < number.length - 1; i++) {
let value = parseInt(number.charAt(i));
if (i % 2 === 0) {
value *= 2;
}
if (value > 9) {
value -= 9;
}
sum += value;
}
return sum % 10 === 0;
}
