JavaScript: Cart.js

cart.js

// cart.js
//
// Copyright 2014 Jeka Kiselyov
// Released under the MIT license, http://opensource.org/licenses/MIT
//
// Usage:
// Cart.add(sku, name, 9.99, qty);
// Cart.remove(sku);
// if (Cart.has(sku)) { ...
// var price = Cart.priceTotal();
// var priceHTML = Cart.priceTotal(true); // '0.00'
// for (var k in Cart.items) { console.log(Cart.items[k]; ...
window.Cart = {
	items: {},
	itemsCount: 0,
	itemsCountTotal: 0,

	domain: false,

	init: function()
	{
		this.loadFromCookies();
	},

	clear: function()
	{
		this.items = {};
		this.itemsCount = 0;
		this.itemsCountTotal = 0;
		this.saveToCookies();

		return true;
	},

	add: function(id, name, price, qty)
	{
		if (typeof(qty) !== 'undefined')
			qty = parseInt(qty, 10);
		else
			qty = 1;

		if (typeof(price) !== 'undefined')
			price = parseFloat(price);
		else
			price = 0;

		if (this.has(id))
		{
			this.items[id].qty+=qty;
		} else {
			this.items[id] = {id: id, name: name, qty: qty, price: price};
			this.itemsCount++;
		}

		this.itemsCountTotal+=qty;
		this.saveToCookies();
		return true;
	},

	remove: function(id)
	{
		if (this.has(id))
		{
			this.itemsCount--;
			this.itemsCountTotal-=this.items[id].qty;

			delete this.items[id];
			this.saveToCookies();

			return true;
		} else {
			throw 'Invalid cart item identified';
		}
	},

	increment: function(id, inc)
	{
		if (typeof(inc) !== 'undefined')
			inc = parseInt(inc, 10);
		else
			inc = 1;

		if (this.has(id))
		{
			if (inc < 0 && -inc >= this.items[id].qty)  /// don't allow to go in minus
			{
				inc = -this.items[id].qty;
				return this.remove(id);
			}

			this.itemsCountTotal+=inc;
			this.items[id].qty+=inc;
			this.saveToCookies();

			return true;
		} else {
			throw 'Invalid cart item identified';
		}		
	},

	has: function(id)
	{
		if (typeof(this.items[id]) !== 'undefined' && typeof(this.items[id].qty) !== 'undefined' && this.items[id].qty > 0)
			return true;
		else
			return false;
	},

	getById: function(id)
	{
		if (this.has(id))
			return this.items[id];
		else {
			throw 'Invalid cart item identified';
		}		
	},

	count: function()
	{
		return this.itemsCount;
	},

	countTotal: function()
	{
		return this.itemsCountTotal;
	},

	priceTotal: function(format)
	{
		var ret = 0;
		for (var k in this.items)
			if (typeof(this.items[k].qty) != 'undefined' && typeof(this.items[k].price) != 'undefined')
				ret+=(this.items[k].price*this.items[k].qty);

		if (format)
		{
			ret = ret.toFixed(2);
		}
		return ret;
	},

	saveToCookies: function()
	{
		try 
		{
			this.docCookies.setItem('cart_items', JSON.stringify(this.items));
			return true;
		} catch (e) {
		}
	},

	loadFromCookies: function()
	{
		var items = {};
		try 
		{
			items = JSON.parse(this.docCookies.getItem('cart_items'));
		} catch (e) {
		}

		for (var k in items)
			if (typeof(items[k].id) !== 'undefined' && typeof(items[k].name) !== 'undefined'
				 && typeof(items[k].qty) !== 'undefined' && typeof(items[k].price) !== 'undefined')
			{
				this.add(items[k].id, items[k].name, items[k].price, items[k].qty);
			}
		return true;
	},

	docCookies: {
		getItem: function (sKey) {
			return decodeURIComponent(document.cookie.replace(new RegExp("(?:(?:^|.*;)\\s*" + encodeURIComponent(sKey).replace(/[\-\.\+\*]/g, "\\$&") + "\\s*\\=\\s*([^;]*).*$)|^.*$"), "$1")) || null;
		},
		setItem: function (sKey, sValue, vEnd, sPath, sDomain, bSecure) {
			if (!sKey || /^(?:expires|max\-age|path|domain|secure)$/i.test(sKey)) { return false; }
			var sExpires = "; expires=Fri, 31 Dec 9999 23:59:59 GMT";
			var sPath = "/";
			if (window.Cart.domain)
				var sDomain = window.Cart.domain;
			else
				var sDomain = '';
			document.cookie = encodeURIComponent(sKey) + "=" + encodeURIComponent(sValue) + sExpires + (sDomain ? "; domain=" + sDomain : "") + (sPath ? "; path=" + sPath : "") + (bSecure ? "; secure" : "");
			return true;
		}
	}
}

Cart.init();