utils.js

function prettyDate(date) {
    var date, seconds, formats, i = 0, f;
    date = new Date(date);
    seconds = (new Date - date) / 1000;
    formats = [
        [-1, 'Recently'], // Deals with times in the future
        [60, 'seconds', 1],
        [120, '1 minute ago'],
        [3600, 'minutes', 60],
        [7200, '1 hour ago'],
        [86400, 'hours', 3600],
        [172800, 'Yesterday'],
        [604800, 'days', 86400],
        [1209600, '1 week ago'],
        [2678400, 'weeks', 604800]
    ];

    while (f = formats[i++]) {
        if (seconds < f[0]) {
            return f[2] ? Math.floor(seconds / f[2]) + ' ' + f[1] + ' ago' : f[1];
        }
        // Crude fix for feed items with incorrect pubDate (i.e. 01 Dec 1999)
        // look for anything over 10 years old
        if (seconds > 315569260) {
            return 'Recently';
        }
    }

    return dateFormat(date, 'longDate');
};


/*
 * Date Format 1.2.3
 * (c) 2007-2009 Steven Levithan <stevenlevithan.com>
 * MIT license
 *
 * Includes enhancements by Scott Trenda <scott.trenda.net>
 * and Kris Kowal <cixar.com/~kris.kowal/>
 *
 * Accepts a date, a mask, or a date and a mask.
 * Returns a formatted version of the given date.
 * The date defaults to the current date/time.
 * The mask defaults to dateFormat.masks.default.
 *
 * http://blog.stevenlevithan.com/archives/date-time-format
 */
var dateFormat = function () {
    var token = /d{1,4}|m{1,4}|yy(?:yy)?|([HhMsTt])\1?|[LloSZ]|"[^"]*"|'[^']*'/g,
        timezone = /\b(?:[PMCEA][SDP]T|(?:Pacific|Mountain|Central|Eastern|Atlantic) (?:Standard|Daylight|Prevailing) Time|(?:GMT|UTC)(?:[-+]\d{4})?)\b/g,
        timezoneClip = /[^-+\dA-Z]/g,
        pad = function (val, len) {
            val = String(val);
            len = len || 2;
            while (val.length < len) val = "0" + val;
            return val;
        };

    // Regexes and supporting functions are cached through closure
    function finalDate(date, mask, utc) {
        // You can't provide utc if you skip other args (use the "UTC:" mask prefix)
        if (arguments.length == 1 && Object.prototype.toString.call(date) == "[object String]" && !/\d/.test(date)) {
            mask = date;
            date = undefined;
        }

        // Passing date through Date applies Date.parse, if necessary
        date = date ? new Date(date) : new Date;
        if (isNaN(date)) throw SyntaxError("invalid date");

        mask = String(dateFormat.masks[mask] || mask || dateFormat.masks["default"]);

        // Allow setting the utc argument via the mask
        if (mask.slice(0, 4) == "UTC:") {
            mask = mask.slice(4);
            utc = true;
        }

        var _ = utc ? "getUTC" : "get",
            d = date[_ + "Date"](),
            D = date[_ + "Day"](),
            m = date[_ + "Month"](),
            y = date[_ + "FullYear"](),
            H = date[_ + "Hours"](),
            M = date[_ + "Minutes"](),
            s = date[_ + "Seconds"](),
            L = date[_ + "Milliseconds"](),
            o = utc ? 0 : date.getTimezoneOffset(),
            flags = {
                d: d,
                dd: pad(d),
                ddd: dateFormat.i18n.dayNames[D],
                dddd: dateFormat.i18n.dayNames[D + 7],
                m: m + 1,
                mm: pad(m + 1),
                mmm: dateFormat.i18n.monthNames[m],
                mmmm: dateFormat.i18n.monthNames[m + 12],
                yy: String(y).slice(2),
                yyyy: y,
                h: H % 12 || 12,
                hh: pad(H % 12 || 12),
                H: H,
                HH: pad(H),
                M: M,
                MM: pad(M),
                s: s,
                ss: pad(s),
                l: pad(L, 3),
                L: pad(L > 99 ? Math.round(L / 10) : L),
                t: H < 12 ? "a" : "p",
                tt: H < 12 ? "am" : "pm",
                T: H < 12 ? "A" : "P",
                TT: H < 12 ? "AM" : "PM",
                Z: utc ? "UTC" : (String(date).match(timezone) || [""]).pop().replace(timezoneClip, ""),
                o: (o > 0 ? "-" : "+") + pad(Math.floor(Math.abs(o) / 60) * 100 + Math.abs(o) % 60, 4),
                S: ["th", "st", "nd", "rd"][d % 10 > 3 ? 0 : (d % 100 - d % 10 != 10) * d % 10]
            };

        return mask.replace(token, function ($0) {
            return $0 in flags ? flags[$0] : $0.slice(1, $0.length - 1);
        });
    };

    return finalDate;
}();


// Some common format strings
dateFormat.masks = {
    "default": "HH:MM:ss dd mmm yyyy ", // 17:46:21 09 Jun 2007
    shortDate: "m/d/yy", // 6/9/07
    mediumDate: "d mmm yyyy", // 9 Jun 2007
    longDate: "d mmmm yyyy", // 9 June 2007
    fullDate: "dddd, mmmm d, yyyy", // Saturday, June 9, 2007
    shortTime: "h:MM TT", // 5:46 PM
    mediumTime: "h:MM:ss TT", // 5:46:21 PM
    longTime: "h:MM:ss TT Z", // 5:46:21 PM EST
    isoDate: "yyyy-mm-dd", // 2007-06-09
    isoTime: "HH:MM:ss", // 17:46:21
    isoDateTime: "yyyy-mm-dd'T'HH:MM:ss", // 2007-06-09T17:46:21
    isoUtcDateTime: "UTC:yyyy-mm-dd'T'HH:MM:ss'Z'", // 2007-06-09T22:46:21Z

    timeDate: "dd mmm; h:MM TT" // 09 Jun; 5:46:21 PM
};


// Internationalization strings
dateFormat.i18n = {
    dayNames: [
        "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat",
        "Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"
    ],
    monthNames: [
        "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec",
        "January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"
    ]
};


// For convenience...
Date.prototype.format = function (mask, utc) {
    return dateFormat(this, mask, utc);
};