REGON

REGON (Rejestr Gospodarki Narodowej) is Poland’s business registry identifier. It exists in two forms:

• 9 digits — for individual entities (sole traders, natural persons).
• 14 digits — for legal entities with local units (the first 9 digits are the base REGON, the last 5 identify the local unit).

Usage

import { Numerik } from '@slashlab/numerik-js'

// Boolean
Numerik.regon().isValid('850518457')        // true (9-digit)
Numerik.regon().isValid('85051845749370')   // true (14-digit)

// Rich result
const result = Numerik.regon().validate('850518457')
result.isValid   // true

// Parse to value object
const regon = Numerik.regon().parse('850518457')

// Null on failure instead of exception
const maybe = Numerik.regon().tryParse('bad-input') // null

Value object API

parse() and tryParse() return a Regon instance.

Core

Method	Return type	Description
getRaw()	string	The original input, untouched.
getNormalized()	string	Whitespace-stripped digits.
toString()	string	Alias for getNormalized().

Type & structure

Method	Return type	Description
getType()	RegonType	RegonType.Individual (9-digit) or RegonType.LegalEntity (14-digit).
getBaseRegon()	string	First 9 digits — always present for both types.
getLocalUnitSuffix()	string | null	Last 5 digits for 14-digit numbers; null for 9-digit.
isLocalUnit()	boolean	true for 14-digit (legal entity with local unit).

Examples

import { Numerik, RegonType } from '@slashlab/numerik-js'

// 9-digit REGON
const regon = Numerik.regon().parse('850518457')

regon.getType()              // RegonType.Individual
regon.getBaseRegon()         // '850518457'
regon.getLocalUnitSuffix()   // null
regon.isLocalUnit()          // false

// 14-digit REGON
const regon14 = Numerik.regon().parse('85051845749370')

regon14.getType()             // RegonType.LegalEntity
regon14.getBaseRegon()        // '850518457'
regon14.getLocalUnitSuffix()  // '49370'
regon14.isLocalUnit()         // true

Failure reasons

Reason	Value	When
InvalidLength	invalid_length	Input is not exactly 9 or 14 digits after normalisation.
InvalidCharacters	invalid_characters	Non-digit characters remain after stripping whitespace.
InvalidChecksum	invalid_checksum	Checksum digit does not match. For 14-digit, can refer to either the base 9-digit check or the full 14-digit check.

Validation algorithm

9-digit weights: 8, 9, 2, 3, 4, 5, 6, 7

14-digit weights: 2, 4, 8, 5, 0, 9, 7, 3, 6, 1, 2, 4, 8

9-digit validation:

1. Strip whitespace. Assert exactly 9 digits.
2. Multiply the first 8 digits by the 9-digit weights, sum, take mod 11. If the result is 10, the checksum digit must be 0. Otherwise the result must equal digit 9.

14-digit validation:

1. Strip whitespace. Assert exactly 14 digits.
2. Validate the first 9 digits as a standalone 9-digit REGON.
3. Multiply all 13 significant digits by the 14-digit weights, sum, take mod 11. If the result is 10, checksum digit must be 0. Otherwise the result must equal digit 14.

See Algorithms for the full reference.