Developer Reference & Snippets
Open Source Guides & Code Snippets
Quick-start references for thutil open-source projects and standalone zero-dependency utility functions.
1. thutil Open Source Projects
GitHub @thutilExplore our open source codebases and try the live web applications below:
2. Thai National ID Validation (Modulo 11 Checksum)
Copy and paste this zero-dependency TypeScript/JavaScript function directly into your application:
function validateThaiCitizenId(id: string): boolean {
const cleanId = id.replace(/[^0-9]/g, '');
if (cleanId.length !== 13) return false;
if (cleanId.charAt(0) === '0') return false;
let sum = 0;
for (let i = 0; i < 12; i++) {
sum += parseInt(cleanId.charAt(i), 10) * (13 - i);
}
const checkDigit = (11 - (sum % 11)) % 10;
return checkDigit === parseInt(cleanId.charAt(12), 10);
}3. CRC16-CCITT Calculation (EMVCo Standard)
Standalone CRC16-CCITT algorithm for computing QR code payloads:
function calculateCRC16(data: string): string {
let crc = 0xFFFF;
for (let i = 0; i < data.length; i++) {
crc ^= data.charCodeAt(i) << 8;
for (let j = 0; j < 8; j++) {
if ((crc & 0x8000) !== 0) {
crc = ((crc << 1) ^ 0x1021) & 0xFFFF;
} else {
crc = (crc << 1) & 0xFFFF;
}
}
}
return crc.toString(16).toUpperCase().padStart(4, '0');
}