The fastest Spanish DNI (NIE / NIF) validation out there — And lighter: 660 bytes.

Installation

// npm
npm i better-dni

// yarn
yarn add better-dni

Usage

isValid / isNIF / isNIE / ctrlChar

import { isValid, isNIF, isNIE, ctrlChar } from "better-dni";

// validates any type of DNI (NIE or NIF)
isValid("Z7662566Y"); //=> true

// checks if it is a valid NIF
isNIF("06672804K"); //=> true

// checks if it is a valid NIE
isNIE("X1302311M"); //=> true

// returns the control letter in upper case
ctrlChar("X1302311M"); //=> 'M'
ctrlChar("X1302311"); //=> 'M'

Generators

NIF

import { randomNIF, randomNIFWith } from "better-dni";

randomNIF(); //=> '31719111H'

// returns a valid random NIF given the control letter
randomNIFWith("C"); // => '95652190C'

// a seed (Number) can be provided and it will always return the same result
randomNIFWith("G", 1); //=> '95652174G'
randomNIFWith("G", 1); //=> '95652174G'

NIE

import { randomNIE, randomNIEWith } from "better-dni";

randomNIE(); //=> 'X1120409X'

// returns a valid random NIE given the first and control letter
randomNIEWith("Y", "C"); //=> 'Y2098020C'
randomNIEWith("Z", "G"); //=> 'Z5670557G'

// a seed (Number) can be provided and it will always return the same result
randomNIEWith("X", "E", 1); //=> 'X2080280E'
randomNIEWith("X", "E", 1); //=> 'X2080280E'

Normalize

// Returns a "clean" dni string removing spaces, dashes, etc.
normalize(" x-9464186_p   "); // => "X9464186P"

Benchmark

better-dni does a similar job as other libraries like dni-js, dni-js-validator, and @willowi/validate-nif but better-dni is built with optimization and speed in mind. Take a look at these benchmark results:

yarn run benchmark

isValid

lib	method	time	diff
better-dni	#isValid	0 s + 365932959 ns
dni-js-validator	#isValid	1 s + 154193500 ns	x3.15 slower
dni-js	#isValid	1 s + 188613500 ns	x3.24 slower
@willowi/validate-nif	#validateNif	4 s + 986185000 ns	x13.62 slower

ctrlChar / getLetter

lib	method	time	diff
better-dni	#ctrlChar	0 s + 423324167 ns
dni-js	#getLetter	0 s + 354445959 ns	x1.16 faster	😲
dni-js-validator	no method	-
@willowi/validate-nif	no method	-

Benchmark on a MacBook M2 Pro (16-inch, 2023) - 16 GB Node v20.7.0

Demo

https://better-dni.singuerinc.com/

Related

• spain-phone - Spanish phone number validation

Reference

https://www.interior.gob.es/opencms/ca/servicios-al-ciudadano/tramites-y-gestiones/dni/calculo-del-digito-de-control-del-nif-nie/