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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

135 lines (127 loc) 5.23 kB
'use strict'; var isRegExp = require('./_is-regexp'); var anObject = require('./_an-object'); var speciesConstructor = require('./_species-constructor'); var advanceStringIndex = require('./_advance-string-index'); var toLength = require('./_to-length'); var callRegExpExec = require('./_regexp-exec-abstract'); var regexpExec = require('./_regexp-exec'); var fails = require('./_fails'); var $min = Math.min; var $push = [].push; var $SPLIT = 'split'; var LENGTH = 'length'; var LAST_INDEX = 'lastIndex'; var MAX_UINT32 = 0xffffffff; // babel-minify transpiles RegExp('x', 'y') -> /x/y and it causes SyntaxError var SUPPORTS_Y = !fails(function () { RegExp(MAX_UINT32, 'y'); }); // @@split logic require('./_fix-re-wks')('split', 2, function (defined, SPLIT, $split, maybeCallNative) { var internalSplit; if ( 'abbc'[$SPLIT](/(b)*/)[1] == 'c' || 'test'[$SPLIT](/(?:)/, -1)[LENGTH] != 4 || 'ab'[$SPLIT](/(?:ab)*/)[LENGTH] != 2 || '.'[$SPLIT](/(.?)(.?)/)[LENGTH] != 4 || '.'[$SPLIT](/()()/)[LENGTH] > 1 || ''[$SPLIT](/.?/)[LENGTH] ) { // based on es5-shim implementation, need to rework it internalSplit = function (separator, limit) { var string = String(this); if (separator === undefined && limit === 0) return []; // If `separator` is not a regex, use native split if (!isRegExp(separator)) return $split.call(string, separator, limit); var output = []; var flags = (separator.ignoreCase ? 'i' : '') + (separator.multiline ? 'm' : '') + (separator.unicode ? 'u' : '') + (separator.sticky ? 'y' : ''); var lastLastIndex = 0; var splitLimit = limit === undefined ? MAX_UINT32 : limit >>> 0; // Make `global` and avoid `lastIndex` issues by working with a copy var separatorCopy = new RegExp(separator.source, flags + 'g'); var match, lastIndex, lastLength; while (match = regexpExec.call(separatorCopy, string)) { lastIndex = separatorCopy[LAST_INDEX]; if (lastIndex > lastLastIndex) { output.push(string.slice(lastLastIndex, match.index)); if (match[LENGTH] > 1 && match.index < string[LENGTH]) $push.apply(output, match.slice(1)); lastLength = match[0][LENGTH]; lastLastIndex = lastIndex; if (output[LENGTH] >= splitLimit) break; } if (separatorCopy[LAST_INDEX] === match.index) separatorCopy[LAST_INDEX]++; // Avoid an infinite loop } if (lastLastIndex === string[LENGTH]) { if (lastLength || !separatorCopy.test('')) output.push(''); } else output.push(string.slice(lastLastIndex)); return output[LENGTH] > splitLimit ? output.slice(0, splitLimit) : output; }; // Chakra, V8 } else if ('0'[$SPLIT](undefined, 0)[LENGTH]) { internalSplit = function (separator, limit) { return separator === undefined && limit === 0 ? [] : $split.call(this, separator, limit); }; } else { internalSplit = $split; } return [ // `String.prototype.split` method // https://tc39.github.io/ecma262/#sec-string.prototype.split function split(separator, limit) { var O = defined(this); var splitter = separator == undefined ? undefined : separator[SPLIT]; return splitter !== undefined ? splitter.call(separator, O, limit) : internalSplit.call(String(O), separator, limit); }, // `RegExp.prototype[@@split]` method // https://tc39.github.io/ecma262/#sec-regexp.prototype-@@split // // NOTE: This cannot be properly polyfilled in engines that don't support // the 'y' flag. function (regexp, limit) { var res = maybeCallNative(internalSplit, regexp, this, limit, internalSplit !== $split); if (res.done) return res.value; var rx = anObject(regexp); var S = String(this); var C = speciesConstructor(rx, RegExp); var unicodeMatching = rx.unicode; var flags = (rx.ignoreCase ? 'i' : '') + (rx.multiline ? 'm' : '') + (rx.unicode ? 'u' : '') + (SUPPORTS_Y ? 'y' : 'g'); // ^(? + rx + ) is needed, in combination with some S slicing, to // simulate the 'y' flag. var splitter = new C(SUPPORTS_Y ? rx : '^(?:' + rx.source + ')', flags); var lim = limit === undefined ? MAX_UINT32 : limit >>> 0; if (lim === 0) return []; if (S.length === 0) return callRegExpExec(splitter, S) === null ? [S] : []; var p = 0; var q = 0; var A = []; while (q < S.length) { splitter.lastIndex = SUPPORTS_Y ? q : 0; var z = callRegExpExec(splitter, SUPPORTS_Y ? S : S.slice(q)); var e; if ( z === null || (e = $min(toLength(splitter.lastIndex + (SUPPORTS_Y ? 0 : q)), S.length)) === p ) { q = advanceStringIndex(S, q, unicodeMatching); } else { A.push(S.slice(p, q)); if (A.length === lim) return A; for (var i = 1; i <= z.length - 1; i++) { A.push(z[i]); if (A.length === lim) return A; } q = p = e; } } A.push(S.slice(p)); return A; } ]; });