cdigit
Version:
Collection of check digit algorithms implemented in JavaScript
49 lines (48 loc) • 1.37 kB
JavaScript
;
/**
* cdigit
*
* @copyright 2018-2021 LiosK
* @license (MIT OR Apache-2.0)
*/
Object.defineProperty(exports, "__esModule", { value: true });
exports.gtin = void 0;
const common_1 = require("./common");
/**
* Standard check digit algorithm for GS1 data structures (including GTIN)
*
* Note: This implementation does not check the length of a number; however, it
* is not recommended to use numbers longer than 18 digits because GS1 General
* Specifications do not explicitly specify an algorithm for them.
*/
class GTIN {
constructor() {
this.name = "gtin";
this.longName = "GTINs (including UPC, EAN, ISBN-13, etc.)";
}
compute(num) {
const ds = String(num).replace(/[^0-9]/g, "");
let sum = 0;
let odd = 1;
for (let i = ds.length - 1; i > -1; i -= 1) {
sum += Number(ds[i]) * (odd ? 3 : 1);
odd ^= 1;
if (sum > 0xffffffffffff) {
// ~2^48 at max
sum %= 10;
}
}
return String(10 - (sum % 10)).slice(-1);
}
generate(num) {
return `${num}${this.compute(num)}`;
}
validate(num) {
const [src, cc] = this.parse(num);
return this.compute(src) === cc;
}
parse(num) {
return common_1.helper.parseTail(num, 1);
}
}
exports.gtin = new GTIN();