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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

50 lines (46 loc) 2.18 kB
'use strict'; var $ = require('../internals/export'); var isObject = require('../internals/is-object'); var isArray = require('../internals/is-array'); var toAbsoluteIndex = require('../internals/to-absolute-index'); var toLength = require('../internals/to-length'); var toIndexedObject = require('../internals/to-indexed-object'); var createProperty = require('../internals/create-property'); var wellKnownSymbol = require('../internals/well-known-symbol'); var arrayMethodHasSpeciesSupport = require('../internals/array-method-has-species-support'); var arrayMethodUsesToLength = require('../internals/array-method-uses-to-length'); var HAS_SPECIES_SUPPORT = arrayMethodHasSpeciesSupport('slice'); var USES_TO_LENGTH = arrayMethodUsesToLength('slice', { ACCESSORS: true, 0: 0, 1: 2 }); var SPECIES = wellKnownSymbol('species'); var nativeSlice = [].slice; var max = Math.max; // `Array.prototype.slice` method // https://tc39.github.io/ecma262/#sec-array.prototype.slice // fallback for not array-like ES3 strings and DOM objects $({ target: 'Array', proto: true, forced: !HAS_SPECIES_SUPPORT || !USES_TO_LENGTH }, { slice: function slice(start, end) { var O = toIndexedObject(this); var length = toLength(O.length); var k = toAbsoluteIndex(start, length); var fin = toAbsoluteIndex(end === undefined ? length : end, length); // inline `ArraySpeciesCreate` for usage native `Array#slice` where it's possible var Constructor, result, n; if (isArray(O)) { Constructor = O.constructor; // cross-realm fallback if (typeof Constructor == 'function' && (Constructor === Array || isArray(Constructor.prototype))) { Constructor = undefined; } else if (isObject(Constructor)) { Constructor = Constructor[SPECIES]; if (Constructor === null) Constructor = undefined; } if (Constructor === Array || Constructor === undefined) { return nativeSlice.call(O, k, fin); } } result = new (Constructor === undefined ? Array : Constructor)(max(fin - k, 0)); for (n = 0; k < fin; k++, n++) if (k in O) createProperty(result, n, O[k]); result.length = n; return result; } });