Introduction

mexico-utils validates, parses and generates the data every Mexican form asks for: CURP, RFC, CLABE, NSS, postal codes, phone numbers and amounts in words. It has no dependencies, ships ESM and CommonJS with types, and runs in Node, browsers and edge runtimes.

Install

npm i mexico-utils

pnpm, yarn and bun work the same way.

Quick look

import { parseCurp, checkRfc, parseClabe, amountToWords } from "mexico-utils";

parseCurp("LOOA531113HTCPBN07");
// { birthDate: "1953-11-13", sex: "male", state: { name: "Tabasco", ... }, bornAbroad: false }

parseClabe("002010077777777771")?.bank;
// { code: "002", name: "Banamex" }

amountToWords(1234.5);
// "MIL DOSCIENTOS TREINTA Y CUATRO PESOS 50/100 M.N."

How the API works

Every document type comes with the same set of functions, so once you know one you know them all:

Function	Returns
`isValidX(value)`	`true` or `false`
`parseX(value)`	The parsed data, or `null`
`checkX(value)`	`{ ok: true, value }` or `{ ok: false, error }`
`xCheckDigit(...)`	The check digit, in case you need to build one

Input gets cleaned before it's checked, so spaces, dashes and lowercase are fine.

Errors in your own words

checkX never returns a message. It returns an error code, and you decide what to show. That way your form speaks the same language as the rest of your app.

const messages = {
  format: "A CURP has 18 characters",
  date: "That birth date doesn't exist",
  state: "Unknown state",
  "check-digit": "Double-check you copied it right",
};

const result = checkCurp(input);
if (!result.ok) showError(messages[result.error]);

The codes are typed, so TypeScript tells you if you forget one.