cdigit
Version:
Collection of check digit algorithms implemented in JavaScript
65 lines (64 loc) • 2.42 kB
JavaScript
;
/**
* cdigit
*
* @copyright 2018-2021 LiosK
* @license (MIT OR Apache-2.0)
*/
Object.defineProperty(exports, "__esModule", { value: true });
exports.helper = void 0;
exports.helper = {
parseTail: (num, n) => {
const ds = String(num);
return [ds.slice(0, -n), ds.slice(-n)];
},
_invCharListMemo: {},
invertCharList: (alphabet) => {
if (exports.helper._invCharListMemo[alphabet] == null) {
exports.helper._invCharListMemo[alphabet] = {};
const len = alphabet.length;
for (let i = 0; i < len; i += 1) {
exports.helper._invCharListMemo[alphabet][alphabet[i]] = i;
}
if (len !== Object.keys(exports.helper._invCharListMemo[alphabet]).length) {
throw new Error("assertion error: chars must be unique");
}
}
return exports.helper._invCharListMemo[alphabet];
},
iso7064: {
numeric: "0123456789X",
alphabetic: "ABCDEFGHIJKLMNOPQRSTUVWXYZ",
alphanumeric: "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ*",
/** Implement ISO 7064 pure system recursive method. */
computePure: (num, mod, radix, hasTwoCCs, alphabet) => {
const ds = `${num}${alphabet[0]}${hasTwoCCs ? alphabet[0] : ""}`;
const overflowProtection = Math.floor(0xffffffffffff / radix);
const charmap = exports.helper.invertCharList(alphabet);
let c = 0;
for (let i = 0, len = ds.length; i < len; i += 1) {
c = c * radix + charmap[ds[i]];
if (c > overflowProtection) {
c %= mod;
}
}
c = (mod + 1 - (c % mod)) % mod;
if (hasTwoCCs) {
return `${alphabet[Math.floor(c / radix)]}${alphabet[c % radix]}`;
}
return alphabet[c];
},
/** Implement ISO 7064 hybrid system recursive method. */
computeHybrid: (ds, alphabet) => {
const mod = alphabet.length;
const charmap = exports.helper.invertCharList(alphabet);
let c = mod;
for (let i = 0, len = ds.length; i < len; i += 1) {
c = (c % (mod + 1)) + charmap[ds[i]];
c = (c % mod || mod) * 2;
}
c %= mod + 1;
return alphabet[(mod + 1 - c) % mod];
},
},
};