Review my JavaScript cookie library

Question

I wrote a small JavaScript libary that aims to simplify JavaScript cookies. You can find the code on Github: https://github.com/js-coder/cookie.js I tested it in various browsers and it seems to work everywhere.

It's not a lot of code so I'll insert it here as well: I updated the code quite a bit so I posted the new version below.

(function (undefined) {
 var isArray = Array.isArray || function (value) { // check if value is an array created with [] or new Array
 return Object.prototype.toString.call(value) === '[object Array]';
 },
 isPlainObj = function (value) { // check if value is an object that was created with {} or new Object
 return Object.prototype.toString.call(value) === '[object Object]';
 },
 getKeys = Object.keys || function (obj) { // Object.keys polyfill
 var keys = [],
 key = '';
 for (key in obj) {
 if (obj.hasOwnProperty(key)) keys.push(key);
 }
 return keys;
 },
 retrieve = function (value, fallback) { // return fallback if the value is undefined, otherwise return value
 return value === undefined ? fallback : value;
 },
 _cookie = {
 set: function (key, value, options) {
 if (isPlainObj(key)) {
 for (var k in key) {
 if (key.hasOwnProperty(k)) this.set(k, key[k]);
 }
 } else {
 options = options || {};
 var expires = options.expires || '',
 expiresType = typeof(expires),
 path = options.path ? ';path=' + options.path : '',
 domain = options.domain ? ';domain=' + options.domain : '',
 secure = options.secure ? ';secure' : '';
 if (expiresType === 'string' && expires !== '') expires = ';expires=' + expires;
 else if (expiresType == 'number') { // this is needed because IE does not support max-age
 var d = new Date;
 d.setTime(d.getTime() + expires);
 expires = ';expires=' + d.toGMTString();
 } else if (expires.hasOwnProperty('toGMTString')) expires = ';expires=' + expires.toGMTString();
 document.cookie = key + '=' + escape(value) + expires + path + domain + secure;
 }
 return this; // return the _cookie object to allow chaining
 },
 remove: function (keys) {
 keys = isArray(keys) ? keys : arguments;
 for (var i = 0, length = keys.length; i < length; i++) {
 this.set(keys[i], '', {
 expires: -60 * 60 * 24
 });
 }
 return this; // return the _cookie object to allow chaining
 },
 empty: function () {
 return this.remove(getKeys(this.all())); // return the _cookie object to allow chaining
 },
 get: function (key, fallback) {
 fallback = fallback || undefined;
 if (isArray(key)) {
 var result = {},
 cookies = this.all();
 for (var i = 0, l = key.length; i < l; i++) {
 var value = key[i];
 result[value] = retrieve(cookies[value], fallback);
 }
 return result;
 } else {
 var cookies = this.all();
 return retrieve(cookies[key], fallback);
 }
 },
 all: function () {
 if (document.cookie == '') return {};
 var match = document.cookie.split('; '),
 results = {};
 for (var i = 0, l = match.length; i < l; i++) {
 var tmp = match[i].split('=');
 results[tmp[0]] = unescape(tmp[1]);
 }
 return results;
 },
 enabled: function () {
 var ret = cookie.set('a', 'b').get('a') === 'b';
 cookie.remove('a');
 return ret;
 }
 },
 cookie = function (key, fallback) {
 return _cookie.get(key, fallback);
 },
 methods = ['set', 'remove', 'empty', 'get', 'all', 'enabled'];
 for (var i = 0, l = methods.length; i < l; i++) { // copy all _cookie methods to cookie
 var method = methods[i];
 cookie[method] = _cookie[method];
 }
 window.cookie = cookie;
}());

You can find the documentation here: https://github.com/js-coder/cookie.js/blob/master/readme.md

I would love to know how I can improve the code or the API.

Answer 1

I think you want to pass on the options argument and filter with hasOwnProperty() so inside of the .set() method this:

 if (isPlainObj(key)) {
 for (var k in key) {
 this.set(k, key[k]);
 }
 }

becomes this:

 if (isPlainObj(key)) {
 for (var k in key) {
 if (key.hasOwnProperty(k)) {
 this.set(k, key[k], options);
 }
 }
 }

• Kevin Reid: Object.prototype.hasOwnProperty.call(key, k); otherwise you have unexpected behavior if your data contains a hasOwnProperty property.
• jfriend00: @KevinReid - if an object has its own override property called hasOwnProperty, then it would seem that it intends to override it. If we always followed your suggestion, we'd never use a native method of an object, we'd always refer to everything from Object.prototype.
• Kevin Reid: I prefer to distinguish between objects-as-data-structures (which this is intending to be as it doesn't read inherited properties etc.) and objects-as-OO with methods and properties, where inheritance is not rejected.
• jfriend00: @KevinReid - But, JS doesn't have data only objects. An object is an object and every object has methods which one should be free to use. I understand the point you're making, but I don't think that's the way JS was designed to be use. You are free to use it that way yourself, I guess.
• js-coder: @jfriend00 I agree with you. BTW I fixed this with the latest update on github. :) github.com/js-coder/cookie.js/blob/master/cookie.js