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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

31 lines (28 loc) 1.13 kB
'use strict'; var $ = require('../internals/export'); var toInteger = require('../internals/to-integer'); var parseInt = require('../internals/number-parse-int'); var INVALID_NUMBER_REPRESENTATION = 'Invalid number representation'; var INVALID_RADIX = 'Invalid radix'; var valid = /^[\da-z]+$/; // `Number.fromString` method // https://github.com/tc39/proposal-number-fromstring $({ target: 'Number', stat: true }, { fromString: function fromString(string, radix) { var sign = 1; var R, mathNum; if (typeof string != 'string') throw TypeError(INVALID_NUMBER_REPRESENTATION); if (!string.length) throw SyntaxError(INVALID_NUMBER_REPRESENTATION); if (string.charAt(0) == '-') { sign = -1; string = string.slice(1); if (!string.length) throw SyntaxError(INVALID_NUMBER_REPRESENTATION); } R = radix === undefined ? 10 : toInteger(radix); if (R < 2 || R > 36) throw RangeError(INVALID_RADIX); if (!valid.test(string) || (mathNum = parseInt(string, R)).toString(R) !== string) { throw SyntaxError(INVALID_NUMBER_REPRESENTATION); } return sign * mathNum; } });