[date timeAgo] method which returns a string like "about a minute"

CPDate-TimeAgo.j

/*
 * Created by Alexander Ljungberg on May 17, 2010.
 * Copyright 2010, WireLoad, LLC All rights reserved.
 *
 * Based on jQuery's timeago by Ryan McGeary.
 *
 * Original code is:
 * Licensed under the MIT:
 * http://www.opensource.org/licenses/mit-license.php
 *
 * Copyright (c) 2008-2010, Ryan McGeary (ryanonjavascript -[at]- mcgeary [*dot*] org)
 */

var TimeAgoSettings = {
    refreshMillis: 60000,
    allowFuture: false,
    strings: {
        prefixAgo: null,
        prefixFromNow: null,
        suffixAgo: "ago",
        suffixFromNow: "from now",
        seconds: "less than a minute",
        minute: "about a minute",
        minutes: "%d minutes",
        hour: "about an hour",
        hours: "about %d hours",
        day: "a day",
        days: "%d days",
        month: "about a month",
        months: "%d months",
        year: "about a year",
        years: "%d years"
    }
};

var distance = function(date) {
    return (new Date().getTime() - date.getTime());
}

var substitute = function(string, value) {
    return string.replace(/%d/i, value);
}

@implementation CPDate (TimeAgo)

- (CPString)timeAgo
{
    var distanceMillis = distance(self),
        l = TimeAgoSettings.strings,
        prefix = l.prefixAgo,
        suffix = l.suffixAgo || l.ago;

    if (TimeAgoSettings.allowFuture)
    {
        if (distanceMillis < 0)
        {
          prefix = l.prefixFromNow;
          suffix = l.suffixFromNow || l.fromNow;
        }
        distanceMillis = Math.abs(distanceMillis);
    }

    var seconds = distanceMillis / 1000,
        minutes = seconds / 60,
        hours = minutes / 60,
        days = hours / 24,
        years = days / 365;

    var words = seconds < 45 && substitute(l.seconds, Math.round(seconds)) ||
        seconds < 90 && substitute(l.minute, 1) ||
        minutes < 45 && substitute(l.minutes, Math.round(minutes)) ||
        minutes < 90 && substitute(l.hour, 1) ||
        hours < 24 && substitute(l.hours, Math.round(hours)) ||
        hours < 48 && substitute(l.day, 1) ||
        days < 30 && substitute(l.days, Math.floor(days)) ||
        days < 60 && substitute(l.month, 1) ||
        days < 365 && substitute(l.months, Math.floor(days / 30)) ||
        years < 2 && substitute(l.year, 1) ||
        substitute(l.years, Math.floor(years));

    return [[prefix, words, suffix].join(" ") stringByTrimmingWhitespace];
}

@end