nordic-id-validator

Lightweight, zero-dependency validator for Nordic personal identification numbers (SSN / personnummer / fødselsnummer / CPR / HETU).

Supports Sweden, Norway, Denmark, and Finland with format, date, and checksum validation.

Installation

npm install nordic-id-validator

Quick start

const Validator = require('nordic-id-validator');
const validator = new Validator();

validator.isValid('860101-3496', 'SE'); // true
validator.isValid('21103426631', 'NO'); // true

Usage

Generic API

Use isValid(input, countryCode) when the country is dynamic:

validator.isValid('860101-3496', 'SE'); // true
validator.isValid('0105949021',  'DK'); // true
validator.isValid('010594Y9021', 'FI'); // true

Country-specific API

Use the country-specific methods when the country is known up front:

validator.isValidSE('860101-3496');  // Sweden
validator.isValidNO('21103426631');  // Norway
validator.isValidDK('0105949021');   // Denmark
validator.isValidFI('010594Y9021');  // Finland

API

Method	Returns	Description
isValid(input, countryCode)	boolean	Validates against the given country code.
isValidSE(input)	boolean	Validates a Swedish personnummer.
isValidNO(input)	boolean	Validates a Norwegian fødselsnummer.
isValidDK(input)	boolean	Validates a Danish CPR-nummer.
isValidFI(input)	boolean	Validates a Finnish HETU.

Supported country codes: SE, NO, DK, FI.

Input types: string (recommended) or number. Number input is supported for convenience but will silently drop leading zeros — prefer strings.

Accepted formats

Country	Length	Example	Separator
SE	10 digits	860101-3496	Optional - between date and serial.
SE	12 digits	19860101-3496	Optional - between date and serial.
NO	11 digits	21103426631	None.
DK	10 digits	030594-9031	Optional - between date and serial.
FI	11 chars	010594Y9021	Century marker is part of the format.

Validation rules per country

• Sweden — length, date of birth, and Luhn check digit.
• Norway — length, date of birth, and both mod-11 check digits.
• Denmark — length and date of birth. The mod-11 checksum was phased out in 2007 and is not validated.
• Finland — HETU format, date of birth, and check character (modulo 31).

Error handling

isValid throws on unknown country codes:

try {
    validator.isValid('860101-3496', 'XX');
} catch (error) {
    console.error(error.message);
    // -> "Invalid country code. Valid country codes are: SE, NO, DK, FI"
}

All methods throw a TypeError if the input is neither a string nor a number:

validator.isValidSE({}); // throws TypeError

Otherwise, validation returns false for malformed input — no exceptions for ordinary invalid numbers.

Contributing

Issues and pull requests are welcome. Please include test cases for any new validation rules or bug fixes.

npm install
npm test
npm run lint

License

MIT — A project by Fiive.