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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 typeOf = require('kind-of'); var copyDescriptor = require('copy-descriptor'); var define = require('define-property'); /** * Copy static properties, prototype properties, and descriptors from one object to another. * * ```js * function App() {} * var proto = App.prototype; * App.prototype.set = function() {}; * App.prototype.get = function() {}; * * var obj = {}; * copy(obj, proto); * ``` * @param {Object} `receiver` * @param {Object} `provider` * @param {String|Array} `omit` One or more properties to omit * @return {Object} * @api public */ function copy(receiver, provider, omit) { if (!isObject(receiver)) { throw new TypeError('expected receiving object to be an object.'); } if (!isObject(provider)) { throw new TypeError('expected providing object to be an object.'); } var props = nativeKeys(provider); var keys = Object.keys(provider); var len = props.length; omit = arrayify(omit); while (len--) { var key = props[len]; if (has(keys, key)) { define(receiver, key, provider[key]); } else if (!(key in receiver) && !has(omit, key)) { copyDescriptor(receiver, provider, key); } } }; /** * Return true if the given value is an object or function */ function isObject(val) { return typeOf(val) === 'object' || typeof val === 'function'; } /** * Returns true if an array has any of the given elements, or an * object has any of the give keys. * * ```js * has(['a', 'b', 'c'], 'c'); * //=> true * * has(['a', 'b', 'c'], ['c', 'z']); * //=> true * * has({a: 'b', c: 'd'}, ['c', 'z']); * //=> true * ``` * @param {Object} `obj` * @param {String|Array} `val` * @return {Boolean} */ function has(obj, val) { val = arrayify(val); var len = val.length; if (isObject(obj)) { for (var key in obj) { if (val.indexOf(key) > -1) { return true; } } var keys = nativeKeys(obj); return has(keys, val); } if (Array.isArray(obj)) { var arr = obj; while (len--) { if (arr.indexOf(val[len]) > -1) { return true; } } return false; } throw new TypeError('expected an array or object.'); } /** * Cast the given value to an array. * * ```js * arrayify('foo'); * //=> ['foo'] * * arrayify(['foo']); * //=> ['foo'] * ``` * * @param {String|Array} `val` * @return {Array} */ function arrayify(val) { return val ? (Array.isArray(val) ? val : [val]) : []; } /** * Returns true if a value has a `contructor` * * ```js * hasConstructor({}); * //=> true * * hasConstructor(Object.create(null)); * //=> false * ``` * @param {Object} `value` * @return {Boolean} */ function hasConstructor(val) { return isObject(val) && typeof val.constructor !== 'undefined'; } /** * Get the native `ownPropertyNames` from the constructor of the * given `object`. An empty array is returned if the object does * not have a constructor. * * ```js * nativeKeys({a: 'b', b: 'c', c: 'd'}) * //=> ['a', 'b', 'c'] * * nativeKeys(function(){}) * //=> ['length', 'caller'] * ``` * * @param {Object} `obj` Object that has a `constructor`. * @return {Array} Array of keys. */ function nativeKeys(val) { if (!hasConstructor(val)) return []; return Object.getOwnPropertyNames(val); } /** * Expose `copy` */ module.exports = copy; /** * Expose `copy.has` for tests */ module.exports.has = has;