genthaiid

Generate, validate, and complete Thai national ID numbers in JavaScript.

The package is ESM-only and exports the generator as the default export.

Installation

npm install genthaiid

Usage

import gen, {
  random,
  verify,
  completeid,
  randomCompleteID,
  getLastDigit,
  getRndInteger,
  thaiIdRegex,
} from "genthaiid";

const id = gen();
console.log(id); // 13-digit Thai ID

console.log(verify(id)); // true
console.log(thaiIdRegex.test(id)); // true

console.log(random(3)); // ["...", "...", "..."]
console.log(randomCompleteID("1100")); // "1100XXXXXXXX"
console.log(getLastDigit("110170020345")); // checksum digit
console.log(getRndInteger(0, 9)); // random integer between 0 and 9

console.log(completeid("11017002034_5"));
// returns every matching ID that fits the placeholder

API

gen()

Returns a random 13-digit Thai ID number as a string.

random(count)

Returns an array of generated Thai ID numbers.

• If count is a number, it uses parseInt(count).
• If count is a numeric string, it decrements the string safely and generates that many IDs.
• If count is invalid, omitted, or not numeric, it returns an array with one generated ID.

Examples:

random(2);     // ["...", "..."]
random("2");  // ["...", "..."]
random(null);  // ["..."]

randomCompleteID(startDigits)

Generates a random 13-digit Thai ID that starts with the provided digits.

• startDigits must be between 4 and 12 digits.
• The first digit must be between 1 and 8 (Thai ID rule).
• Remaining digits are randomly generated.
• Returns a valid 13-digit Thai ID string that always passes verify().
• Returns undefined if the input is invalid (fewer than 4 digits, first digit is 0 or 9, or contains non-digits).

Examples:

randomCompleteID("1100");      // "1100XXXXXXXX7" (random fill)
randomCompleteID("1234567");   // "1234567XXXXX2" (random fill)
randomCompleteID("110");       // undefined (too few digits)
randomCompleteID("9100");      // undefined (first digit must be 1-8)

verify(id, checkfirstdigit = true, checklastdigit = true)

Checks whether a value is a valid Thai ID.

• Requires exactly 13 digits.
• By default, validates both the first digit rule and the checksum digit.
• checkfirstdigit enforces the first digit to be between 1 and 8.
• checklastdigit enforces the calculated checksum.

completeid(idWithPlaceholders, checkfirstdigit = true, checklastdigit = true)

Completes a partial 13-digit Thai ID using _ as a placeholder and returns every valid match.

Examples:

completeid("11017002034_5");
completeid("1____________");

Returns:

• string[] when multiple candidates are checked and valid matches are found
• string when the original input is already valid
• undefined when the input is not a 13-digit pattern

getLastDigit(firstTwelveDigits)

Calculates the checksum digit from the first 12 digits of a Thai ID.

getRndInteger(min, max)

Returns a random integer between min and max, inclusive.

thaiIdRegex

Regular expression for the first-digit rule:

/^[1-8]\d{12}$/

TypeScript

The package ships with declarations in index.d.ts.

License

MIT