Damm A check digit algorithm, Damm Algorithm (ja) in JavaScript (ES module) Damm.js how to use import { Damm } from "https://code4fukui.github.io/Damm/Damm.js"; console.log(Damm.calc(572)); // 4 console.log(Damm.check(5724)); // true console.log(Damm.addCheckDigit(572)); // 5724 test deno test sample app Damm.js test related Verhoeff Luhn