How to validate BSN, PGN & OWN in the Netherlands with TypeScript/JavaScript

The BSN, PGN and OWN in the Netherlands can be validated with a 11 proef (elf proef). In this post I show you the JavaScript and TypeScript code.

In the Netherlands, we have a few identification numbers from the government. In this example, you can create a function to validate both of them based on the specification.

• BSN = Burgerservice nummer
• PGN = Burgerservice nummer in schools where the student doesn't have a BSN. The PGN is also called OWN.

How to use the code?

Define the function in your code and call it like this:

TypeScript example

// PGN/OWN
elfProefValidation('114435231', ElfproefType.own); // returns true;
elfProefValidation('34564366349', ElfproefType.own); // returns false;
// BSN
elfProefValidation('232262536', ElfproefType.bsn); // returns true;
elfProefValidation('247594057', ElfproefType.bsn); // returns false;

JavaScript example

// PGN/OWN
elfProefValidation('114435231', 'own'); // returns true;
elfProefValidation('34564366349', 'own')); // returns false;
// BSN
elfProefValidation('232262536', 'bsn')); // returns true;
elfProefValidation('247594057', 'bsn')); // returns false;

Working version

I created a working version on RunKit . Make sure you select Node version 17.

function elfProefValidation(value, type) { let returnValue = false; if (!value || value.length === 0) { // This is to prevent behaviour that looks like the OWN is required return true; } if (value === '00000000000' || value.length !== 9) { return false; } const values = value.split(''); const lastCharacter = parseInt(values[values.length - 1], 10); const [a, b, c, d, e, f, g, h, i] = values.map((char) => parseInt(char, 10)); let result = 0; if (type === 'bsn') { result = 9 * a + 8 * b + 7 * c + 6 * d + 5 * e + 4 * f + 3 * g + 2 * h + -1 * i; returnValue = result > 0 && result % 11 === 0; } else if (type === 'own') { result = 9 * a + 8 * b + 7 * c + 6 * d + 5 * e + 4 * f + 3 * g + 2 * h; returnValue = result > 0 && result % 11 === lastCharacter + 5; } else { returnValue = false; } return returnValue; } const bsn = '010464554'; const own = '101211151'; console.log('BSN: ', elfProefValidation(bsn, 'bsn')); console.log('OWN: ', elfProefValidation(own, 'own'));

Code

	function elfProefValidation(value, type) {
	let returnValue = false;
	if (!value || value?.length === 0) {
	return true;
	}
	if (value === '00000000000' || value.length !== 9) {
	return false;
	}
	const values = value.split('');
	const firstCharacter = parseInt(values[0], 10);
	const lastCharacter = parseInt(values[values.length - 1], 10);
	const [a, b, c, d, e, f, g, h, i] = values.map((char) => parseInt(char, 10));
	let result = 0;
	if (type === 'bsn') {
	result = 9 * a + 8 * b + 7 * c + 6 * d + 5 * e + 4 * f + 3 * g + 2 * h + -1 * i;
	returnValue = result > 0 && result % 11 === 0;
	} else if (type === 'own') {
	result = 9 * a + 8 * b + 7 * c + 6 * d + 5 * e + 4 * f + 3 * g + 2 * h;
	returnValue = result > 0 && firstCharacter === 1 && result % 11 === lastCharacter + 5;
	} else {
	returnValue = false;
	}
	return returnValue;
	}

view raw elfproef.validation.js hosted with ❤ by GitHub

	export enum ElfproefType {
	bsn,
	own
	}
	function elfProefValidation(value: string, type: ElfproefType): boolean {
	let returnValue = false;
	if (!value || value?.length === 0) {
	return true;
	}
	if (value === '00000000000' || value.length !== 9) {
	return false;
	}
	const values = value.split('');
	const firstCharacter = parseInt(values[0], 10);
	const lastCharacter = parseInt(values[values.length - 1], 10);
	const [a, b, c, d, e, f, g, h, i] = values.map((char: string) => parseInt(char, 10));
	let result = 0;
	if (type === ElfproefType.bsn) {
	result = 9 * a + 8 * b + 7 * c + 6 * d + 5 * e + 4 * f + 3 * g + 2 * h + -1 * i;
	returnValue = result > 0 && result % 11 === 0;
	} else if (type === ElfproefType.own) {
	result = 9 * a + 8 * b + 7 * c + 6 * d + 5 * e + 4 * f + 3 * g + 2 * h;
	returnValue = result > 0 && firstCharacter === 1 && result % 11 === lastCharacter + 5;
	} else {
	returnValue = false;
	}
	return returnValue;
	}

view raw elfproef.validation.ts hosted with ❤ by GitHub

Thanks!

I hope you learned something new or are inspired to create something new after reading this story! 🤗 If so, consider subscribing via email (scroll to the top of this page) or follow me here on Hashnode.

Did you know that you can create a Developer blog like this one, yourself? It's entirely for free. 👍💰🎉🥳🔥

If I left you with questions or something to say as a response, scroll down and type me a message. Please send me a DM on Twitter @DevByRayRay when you want to keep it private. My DM's are always open 😁