checkLuhn.js

const  checkLuhn = (value) => 
  String(value)
    .replace(/\D/g, '')
    .split('')
    .reverse()
    .map(Number)
    .reduce((sum, digit, i) => {
      if (i % 2 === 1) {
        const doubled = digit * 2;
        return sum + (doubled > 9 ? doubled - 9 : doubled);
      }
      return sum + digit;
    }, 0) % 10 === 0;


console.log(checkLuhn("79927398713")); // true
console.log(checkLuhn("4111-1111-1111-1111")); // true (Visa Test)
console.log(checkLuhn(123456789));