#luhn-algorithm code explainers

java

public final class SensitiveDataMasker {
 
    private static final Pattern CARD_NUMBER = Pattern.compile("\\b(?:\\d[ -]*?){13,19}\\b");
    private static final Pattern EMAIL = Pattern.compile("[A-Za-z0-9._%+-]+@([A-Za-z0-9.-]+\\.[A-Za-z]{2,})");

Masking sensitive data with regex in Java

regex data-masking luhn-algorithm

Intermediate 8 steps

typescript

export function isValidCardNumber(input: string): boolean {
  const digits = input.replace(/[\s-]/g, "");
 
  if (!/^\d{12,19}$/.test(digits)) {

Validating card numbers with the Luhn check

luhn-algorithm checksum input-validation

Intermediate 7 steps

ruby

module CreditCard
  module_function
 
  def valid?(number)

Validating credit card numbers with Luhn

checksum luhn-algorithm validation

Intermediate 6 steps

python

def is_valid_card_number(number: str) -> bool:
    digits = [int(c) for c in number if c.isdigit()]
 
    if len(digits) < 13 or len(digits) > 19:

Validating card numbers with the Luhn check

checksum validation luhn-algorithm

Intermediate 6 steps

javascript

function isValidCardNumber(input) {
  const digits = String(input).replace(/[\s-]/g, '');
 
  if (!/^\d{13,19}$/.test(digits)) {

Validating card numbers with Luhn

checksum validation luhn-algorithm

Intermediate 7 steps