@azizbecha/strkit
Version:
strkit is a utility library offering a collection of essential string functions including validation, case conversion, truncation, and more. Ideal for both JavaScript and TypeScript developers to simplify string operations in their applications.
37 lines • 1.35 kB
JavaScript
/**
* Validates whether a given string is a valid credit card number using the Luhn algorithm.
*
* @param str - The string to check if it's a valid credit card number.
* @returns A boolean indicating whether the string is a valid credit card number.
*
* @example
* isCreditCard("4111111111111111"); // Output: true
* isCreditCard("1234567812345670"); // Output: false
* isCreditCard("not-a-credit-card"); // Output: false
*/
export default function isCreditCard(str) {
// Remove non-numeric characters
const cleaned = str.replace(/\D/g, '');
// Check if the string contains only digits and has a valid length
if (!/^\d{13,19}$/.test(cleaned)) {
return false;
}
// Apply the Luhn algorithm to check for a valid credit card number
let sum = 0;
let shouldDouble = false;
// Start from the rightmost digit
for (let i = cleaned.length - 1; i >= 0; i--) {
let digit = parseInt(cleaned.charAt(i));
if (shouldDouble) {
digit *= 2;
if (digit > 9) {
digit -= 9; // Subtract 9 if the doubled value is greater than 9
}
}
sum += digit;
shouldDouble = !shouldDouble;
}
// A valid credit card number will result in a sum divisible by 10
return sum % 10 === 0;
}
//# sourceMappingURL=isCreditCard.js.map