Pemula Exercism • javascript

ISBN Verifier

Ringkasan Tantangan

Check if a given string is a valid ISBN-10 number.

Source: Exercism javascript/isbn-verifier

💡 Lihat Solusi

export const isValid = (isbn) => {
  const clean = isbn.replace(/-/g, '');
  if (clean.length !== 10) return false;
  
  let sum = 0;
  for (let i = 0; i < 10; i++) {
    const char = clean[i];
    let val;
    if (i === 9 && char === 'X') {
      val = 10;
    } else if (/[0-9]/.test(char)) {
      val = parseInt(char, 10);
    } else {
      return false;
    }
    sum += val * (10 - i);
  }
  
  return sum % 11 === 0;
};