Elfproef

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'));