luhn-generator/update/node_modules/core-js-pure/internals/uid.js

A generator of numbers that passes the validation of Luhn algorithm or Luhn formula, also known as the 'modulus 10' or 'mod 10' algorithm

var id = 0;
var postfix = Math.random();

module.exports = function (key) {
  return 'Symbol(' + String(key === undefined ? '' : key) + ')_' + (++id + postfix).toString(36);
};