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luhn-generator

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

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'use strict'; var GetIntrinsic = require('../GetIntrinsic'); var $Number = GetIntrinsic('%Number%'); var $TypeError = GetIntrinsic('%TypeError%'); var $isNaN = require('../helpers/isNaN'); var $isFinite = require('../helpers/isFinite'); var isPrefixOf = require('../helpers/isPrefixOf'); var ToNumber = require('./ToNumber'); var ToPrimitive = require('./ToPrimitive'); var Type = require('./Type'); // https://www.ecma-international.org/ecma-262/5.1/#sec-11.8.5 // eslint-disable-next-line max-statements module.exports = function AbstractRelationalComparison(x, y, LeftFirst) { if (Type(LeftFirst) !== 'Boolean') { throw new $TypeError('Assertion failed: LeftFirst argument must be a Boolean'); } var px; var py; if (LeftFirst) { px = ToPrimitive(x, $Number); py = ToPrimitive(y, $Number); } else { py = ToPrimitive(y, $Number); px = ToPrimitive(x, $Number); } var bothStrings = Type(px) === 'String' && Type(py) === 'String'; if (!bothStrings) { var nx = ToNumber(px); var ny = ToNumber(py); if ($isNaN(nx) || $isNaN(ny)) { return undefined; } if ($isFinite(nx) && $isFinite(ny) && nx === ny) { return false; } if (nx === 0 && ny === 0) { return false; } if (nx === Infinity) { return false; } if (ny === Infinity) { return true; } if (ny === -Infinity) { return false; } if (nx === -Infinity) { return true; } return nx < ny; // by now, these are both nonzero, finite, and not equal } if (isPrefixOf(py, px)) { return false; } if (isPrefixOf(px, py)) { return true; } return px < py; // both strings, neither a prefix of the other. shortcut for steps c-f };