cookie.js

Cookie = {};

(function(exports) {

    // Cookie
    // -------------
    // Thanks to:
    //  - http://www.nczonline.net/blog/2009/05/05/http-cookies-explained/
    //  - http://developer.yahoo.com/yui/3/cookie/


    var Cookie = exports;

    var decode = decodeURIComponent;
    var encode = encodeURIComponent;


    /**
     * Returns the cookie value for the given name.
     *
     * @param {String} name The name of the cookie to retrieve.
     *
     * @param {Function|Object} options (Optional) An object containing one or
     *     more cookie options: raw (true/false) and converter (a function).
     *     The converter function is run on the value before returning it. The
     *     function is not used if the cookie doesn't exist. The function can be
     *     passed instead of the options object for conveniently. When raw is
     *     set to true, the cookie value is not URI decoded.
     *
     * @return {*} If no converter is specified, returns a string or undefined
     *     if the cookie doesn't exist. If the converter is specified, returns
     *     the value returned from the converter.
     */
    Cookie.get = function(name, options) {
        validateCookieName(name);

        if (typeof options === 'function') {
            options = { converter: options };
        }
        else {
            options = options || {};
        }

        var cookies = parseCookieString(document.cookie, !options['raw']);
        return (options.converter || same)(cookies[name]);
    };


    /**
     * Sets a cookie with a given name and value.
     *
     * @param {string} name The name of the cookie to set.
     *
     * @param {*} value The value to set for the cookie.
     *
     * @param {Object} options (Optional) An object containing one or more
     *     cookie options: path (a string), domain (a string),
     *     expires (number or a Date object), secure (true/false),
     *     and raw (true/false). Setting raw to true indicates that the cookie
     *     should not be URI encoded before being set.
     *
     * @return {string} The created cookie string.
     */
    Cookie.set = function(name, value, options) {
        validateCookieName(name);

        options = options || {};
        var expires = options['expires'];
        var domain = options['domain'];
        var path = options['path'];

        if (!options['raw']) {
            value = encode(String(value));
        }

        var text = name + '=' + value;

        // expires
        var date = expires;
        if (typeof date === 'number') {
            date = new Date();
            date.setDate(date.getDate() + expires);
        }
        if (date instanceof Date) {
            text += '; expires=' + date.toUTCString();
        }

        // domain
        if (isNonEmptyString(domain)) {
            text += '; domain=' + domain;
        }

        // path
        if (isNonEmptyString(path)) {
            text += '; path=' + path;
        }

        // secure
        if (options['secure']) {
            text += '; secure';
        }

        document.cookie = text;
        return text;
    };


    /**
     * Removes a cookie from the machine by setting its expiration date to
     * sometime in the past.
     *
     * @param {string} name The name of the cookie to remove.
     *
     * @param {Object} options (Optional) An object containing one or more
     *     cookie options: path (a string), domain (a string),
     *     and secure (true/false). The expires option will be overwritten
     *     by the method.
     *
     * @return {string} The created cookie string.
     */
    Cookie.remove = function(name, options) {
        options = options || {};
        options['expires'] = new Date(0);
        return this.set(name, '', options);
    };


    function parseCookieString(text, shouldDecode) {
        var cookies = {};

        if (isString(text) && text.length > 0) {

            var decodeValue = shouldDecode ? decode : same;
            var cookieParts = text.split(/;\s/g);
            var cookieName;
            var cookieValue;
            var cookieNameValue;

            for (var i = 0, len = cookieParts.length; i < len; i++) {

                // Check for normally-formatted cookie (name-value)
                cookieNameValue = cookieParts[i].match(/([^=]+)=/i);
                if (cookieNameValue instanceof Array) {
                    try {
                        cookieName = decode(cookieNameValue[1]);
                        cookieValue = decodeValue(cookieParts[i]
                                .substring(cookieNameValue[1].length + 1));
                    } catch (ex) {
                        // Intentionally ignore the cookie -
                        // the encoding is wrong
                    }
                } else {
                    // Means the cookie does not have an "=", so treat it as
                    // a boolean flag
                    cookieName = decode(cookieParts[i]);
                    cookieValue = '';
                }

                if (cookieName) {
                    cookies[cookieName] = cookieValue;
                }
            }

        }

        return cookies;
    }


    // Helpers

    function isString(o) {
        return typeof o === 'string';
    }

    function isNonEmptyString(s) {
        return isString(s) && s !== '';
    }

    function validateCookieName(name) {
        if (!isNonEmptyString(name)) {
            throw new TypeError('Cookie name must be a non-empty string');
        }
    }

    function same(s) {
        return s;
    }

})(Cookie);