Aadhaar

Name: indycheck
Author: dusmamud

Validates an Aadhaar number: exactly 12 digits, first digit 2–9, and the last digit must satisfy the Verhoeff checksum — the same check UIDAI uses. Spaces and dashes are ignored, so 2345 6789 0124 validates the same as 234567890124.

Rules

Rule	Detail
Length	Exactly 12 digits
First digit	2–9 (Aadhaar never starts with 0 or 1)
Characters	Digits only, ignoring spaces and `-`
Checksum	Verhoeff — catches every single-digit typo and most transpositions

Usage

import { validateAadhaar } from 'indycheck';

validateAadhaar('234567890124');
// { ok: true, code: 'VALID', normalized: '234567890124',
//   parsed: { masked: 'XXXX XXXX 0124' } }

validateAadhaar('2345 6789 0124'); // ok: true — spaces ignored
validateAadhaar('234567890123');   // ok: false, code: 'INVALID_CHECKSUM'

from indycheck import validate_aadhaar

r = validate_aadhaar("234567890124")
print(r.parsed["masked"])  # XXXX XXXX 0124

use indycheck::validate_aadhaar;

let r = validate_aadhaar("234567890124");
assert!(r.ok);

Examples

Input	Result	Code
`234567890124`	Valid (Verhoeff passes)	`VALID`
`871366569991`	Valid	`VALID`
`2345 6789 0124`	Valid (spaces ignored)	`VALID`
`234567890123`	Invalid — checksum fails	`INVALID_CHECKSUM`
`123456789012`	Invalid — starts with 1	`INVALID_FIRST_DIGIT`
`23456789012`	Invalid — 11 digits	`INVALID_LENGTH`
`23456789012A`	Invalid — letter inside	`INVALID_FORMAT`
(empty)	Invalid	`EMPTY`

Error codes

Code	Means
`EMPTY`	Nothing was passed in
`INVALID_FORMAT`	Non-digit characters (other than spaces / `-`)
`INVALID_LENGTH`	Not exactly 12 digits
`INVALID_FIRST_DIGIT`	First digit is 0 or 1
`INVALID_CHECKSUM`	Verhoeff checksum failed — mistyped or fake number

Parsed output

On success, parsed contains:

{ "masked": "XXXX XXXX 0124" }

Use the masked value everywhere — in logs, in your database, in API responses. You almost never need the full number after validation.