Script to calculate how older is some date

DateDiff.js

;(function(win) {
    'use strict';
 
    /*
     * CONSTRUCTOR
     */
    function DateDiff(date) {
        this.date = new Date(date);
        this.dateNow = new Date();
    }
 
    /*
     * PUBLIC
     */
    DateDiff.prototype = {
        constructor: DateDiff,
 
        minutes: function() {
            return toInt((this.dateNow - this.date) / 36e5 * 60);
        },
 
        hours: function() {
            return toInt(this.minutes(this.dateNow, this.date) / 60);
        },
 
        days: function() {
            return toInt(this.hours(this.dateNow, this.date) / 24);
        },
 
        weeks: function() {
            return toInt(this.days(this.dateNow, this.date) / 7);
        },
 
        months: function() {
            var d1Y = this.dateNow.getFullYear(),
                d2Y = this.date.getFullYear(),
                d1M = this.dateNow.getMonth(),
                d2M = this.date.getMonth();
 
            return toInt((d1M + 12 * d1Y) - (d2M + 12 * d2Y));
        },
 
        time: function() {
            var minuteDiff = this.minutes(this.dateNow, this.date),
                hourDiff   = this.hours(this.dateNow, this.date),
                dayDiff    = this.days(this.dateNow, this.date),
                weekDiff   = this.weeks(this.dateNow, this.date),
                monthDiff  = this.months(this.dateNow, this.date);
 
            return minuteDiff  <= 60 ? text('minute', minuteDiff)
                   : hourDiff  <= 24 ? text('hour', hourDiff)
                   : dayDiff   <= 7  ? text('day', dayDiff)
                   : weekDiff  <= 4  ? text('week', weekDiff)
                   : text('month', monthDiff);
        }
    }
 
    /*
     * PRIVATE
     */
     function toInt(n) {
        return parseInt(Math.abs(n));
    }
 
    function text(type, number) {
        var text = '',
            n = number > 1 ? false : true;
 
        switch (type) {
            case 'minute':
                text = n ? 'minute' : 'minutes'
                break;
            case 'hour':
                text = n ? 'hour' : 'hours'
                break;
            case 'day':
                text = n ? 'day' : 'days'
                break;
            case 'week':
                text = n ? 'week' : 'weeks'
                break;
            case 'month':
                text = n ? 'month' : 'months'
                break;
        }
 
        return number + ' ' + text + ' ago';
    }
 
    /*
     * GLOBAL
     */
    win.DateDiff = DateDiff;
})(window, document);