@mommo-codes/barkod

GTIN parsing, canonicalisation, match keys and GS1 classification. Written in Rust, compiled to WebAssembly — the same implementation the Rust crate and the Python package run, so all three give the same answers.

Scoped because npm rejects the bare name barkod as too similar to marked. The crate and the Python package are unscoped.

npm install @mommo-codes/barkod

The scoped package starts at 0.1.1; there is no 0.1.0 on npm.

import * as barkod from "@mommo-codes/barkod";

await barkod.init(); // loads the wasm once, at start-up

barkod.storeForm("7350053850019"); // "07350053850019" — padded, check digit kept
barkod.storeForm("lek");           // "lek"            — untouched, never blanked
barkod.key("7350053850019");       // "07350053850010"
barkod.key("073905259077450");     // undefined        — 15 digits is not a GTIN

const p = barkod.parse("370245100000000123");
p.isGtin;  // false
p.reason;  // "too_long"
p.message; // "More than 14 digits — not a GTIN"
p.raw;     // "370245100000000123" — always kept

Every function throws until init() resolves, rather than returning a placeholder. A library that quietly answered wrongly while warming up would be a worse version of the bug this one exists to remove.

The domain

Every function agrees that a GTIN is 8 to 14 digits and differs only on what it does inside that range. Outside it, storeForm hands the input back untouched and key returns undefined. A lossy transformation is not a licence to be more permissive about what counts as a GTIN.

The key is not a GTIN

key() returns a branded GtinKey, not a plain string. It will not assign into a Gtin14String, so the compiler refuses the mistake this library was written to end: writing a match key into a column that holds GTINs. Roughly nine in ten keys end in a check digit no product has.

const k = barkod.key("7390525907745");
const g: barkod.Gtin14String = k; // ✗ does not compile

The brand is compile-time only, so it protects typed slots rather than untyped ones — type your GTIN columns and the guard works.

Full documentation: https://github.com/mommo-codes/barkod

MIT licensed.