Implemented credit card validator according to Sprint 3 stretch requirements

Author: Richiealx

Sprint-3/4-stretch/card-validator.js

@@ -0,0 +1,24 @@
+function validateCreditCard(number) {
+  // Ensure number is 16 digits and only contains digits
+  if (number.length !== 16 || !/^\d+$/.test(number)) return false;
+
+  // Ensure at least 2 different digits are present
+  const uniqueDigits = new Set(number);
+  if (uniqueDigits.size < 2) return false;
+
+  // Ensure the last digit is even
+  const lastDigit = parseInt(number[number.length - 1], 10);
+  if (lastDigit % 2 !== 0) return false;
+
+  // Ensure the sum of digits is greater than 16
+  const sum = number.split('').reduce((acc, digit) => acc + parseInt(digit, 10), 0);
+  if (sum <= 16) return false;
+
+  // If all checks pass, the number is valid
+  return true;
+}
+// Function to validate a credit card number according to the rules in card-validator.md
+
+console.log(validateCreditCard('9999777788880000')); // true
+console.log(validateCreditCard('4444444444444444')); // false
+console.log(validateCreditCard('6666666666666661')); // false