luhn-generator
Version:
A generator of numbers that passes the validation of Luhn algorithm or Luhn formula, also known as the 'modulus 10' or 'mod 10' algorithm
70 lines (67 loc) • 2.79 kB
JavaScript
;
var global = require('./_global');
var has = require('./_has');
var cof = require('./_cof');
var inheritIfRequired = require('./_inherit-if-required');
var toPrimitive = require('./_to-primitive');
var fails = require('./_fails');
var gOPN = require('./_object-gopn').f;
var gOPD = require('./_object-gopd').f;
var dP = require('./_object-dp').f;
var $trim = require('./_string-trim').trim;
var NUMBER = 'Number';
var $Number = global[NUMBER];
var Base = $Number;
var proto = $Number.prototype;
// Opera ~12 has broken Object#toString
var BROKEN_COF = cof(require('./_object-create')(proto)) == NUMBER;
var TRIM = 'trim' in String.prototype;
// 7.1.3 ToNumber(argument)
var toNumber = function (argument) {
var it = toPrimitive(argument, false);
if (typeof it == 'string' && it.length > 2) {
it = TRIM ? it.trim() : $trim(it, 3);
var first = it.charCodeAt(0);
var third, radix, maxCode;
if (first === 43 || first === 45) {
third = it.charCodeAt(2);
if (third === 88 || third === 120) return NaN; // Number('+0x1') should be NaN, old V8 fix
} else if (first === 48) {
switch (it.charCodeAt(1)) {
case 66: case 98: radix = 2; maxCode = 49; break; // fast equal /^0b[01]+$/i
case 79: case 111: radix = 8; maxCode = 55; break; // fast equal /^0o[0-7]+$/i
default: return +it;
}
for (var digits = it.slice(2), i = 0, l = digits.length, code; i < l; i++) {
code = digits.charCodeAt(i);
// parseInt parses a string to a first unavailable symbol
// but ToNumber should return NaN if a string contains unavailable symbols
if (code < 48 || code > maxCode) return NaN;
} return parseInt(digits, radix);
}
} return +it;
};
if (!$Number(' 0o1') || !$Number('0b1') || $Number('+0x1')) {
$Number = function Number(value) {
var it = arguments.length < 1 ? 0 : value;
var that = this;
return that instanceof $Number
// check on 1..constructor(foo) case
&& (BROKEN_COF ? fails(function () { proto.valueOf.call(that); }) : cof(that) != NUMBER)
? inheritIfRequired(new Base(toNumber(it)), that, $Number) : toNumber(it);
};
for (var keys = require('./_descriptors') ? gOPN(Base) : (
// ES3:
'MAX_VALUE,MIN_VALUE,NaN,NEGATIVE_INFINITY,POSITIVE_INFINITY,' +
// ES6 (in case, if modules with ES6 Number statics required before):
'EPSILON,isFinite,isInteger,isNaN,isSafeInteger,MAX_SAFE_INTEGER,' +
'MIN_SAFE_INTEGER,parseFloat,parseInt,isInteger'
).split(','), j = 0, key; keys.length > j; j++) {
if (has(Base, key = keys[j]) && !has($Number, key)) {
dP($Number, key, gOPD(Base, key));
}
}
$Number.prototype = proto;
proto.constructor = $Number;
require('./_redefine')(global, NUMBER, $Number);
}